Any KIA (King Indian Attack) experts right here?

Play e5 when? On move 1? 

If Black plays 1...e5? then you take the pawn with your knight... 

No, she is playing it via the 1.e4 move order.  Avoids the reversed Kings Indian and instead goes for KIA vs Sicilian, French, or Caro-kann.  Down side is you need a system for 1...e5 and 1...d5.

Oh, ok. 

It can be protected by major pieces on the e-file, a Bishop on f4 or b2, knights on f3/g4. Search a database for samples, you will find plenty. I'm certainly not an expert, but in my KIA games with a pawn on e5 I never had difficulties protecting it (without playing d4) when I mindlessly followed the standard plan .

Edit: of course , sometimes d4 is perfectly fine.

2nd edit: note that the e5 advance needs to be prepared and can't be forced. Black has to consent to it. If they don't, its of course still a KIA, but you will need an alternative strategy.

Possibly of interest:

https://www.chess.com/article/view/has-the-king-s-indian-attack-been-forgotten
The KIA is discussed in Winning Chess Openings by GM Yasser Seirawan (1999).
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
For more on the KIA, one could try The King's Indian Attack: Move by Move by Grandmaster Neil McDonald (2014).
https://www.newinchess.com/media/wysiwyg/product_pdf/7277.pdf
Perhaps, it would be of interest to look at The Fianchetto Solution by Emmanuel Neiman and Samy Shoker (2016)
https://www.newinchess.com/media/wysiwyg/product_pdf/9029.pdf
and Starting Out: King's Indian Attack by John Emms (2005).
https://web.archive.org/web/20140627034051/http://www.chesscafe.com/text/hansen81.pdf

Many decades ago, the late GM Evans wrote a book that suggested 1 e4 and going for the King's Indian Attack. If I remember correctly, he advocated something like the Glek System as a reaction to 1...e5.

If Black doesn't want you to play e5, you won't be able to do it, so I'd let go the "as fast as possible" approach. With the KIA you don't put much pressure on the center early on and Black can choose between a lot of pawn structures, each requiring different strategical approaches. While you are playing a system where your own first moves are more or less the same every time, that doesn't mean that the same set of plans will work no matter what Black does. The contrary is the case.

Regarding Black attacking your e5 pawn with f6: you always have to keep that in mind, but very often exf6 is to your advantage. But that totally depends on the given position. There is no universal recipe.

Side note @OP. I don't know about your motives to try the KIA, but my original fascination by it came from the fact that it seemed easy to get a playable position out of the opening instead of being crushed on move 15 in a messy position. So I was crushed on move 25 instead. Don't get fooled like me.  Don't get me wrong, I like the KIA a lot. But If you want to improve your playing strength (of course there are other motives to study chess), the KIA won't help you (yes it will, but not as you think). Go where it hurts and play the open games. Sooner or later, tactics will get you anyway.

Yeah, if you enjoyed playing the game, everything is fine. Just saying that it's not the fastest way to improve. And if you are good enough to choose viable plans for all the very different possible Black setups, also fine. But look at it this way: if you let two non-masters play a game of chess, the better tactician will usually win, even if the loser might be a strategical genius. So if you want to improve your game, improve your tactics and play openings where you don't have to spend 30 minutes on move 15 to figure out a plan that will hopefully give you a better endgame 40 moves later. To forge a plan you need to know and understand the tactical and technical resources to realize it. First things first.

Last but not least: there is a reason that positional skills are considered advanced. They are.

That being said: I used to play the KIA exclusively. But when I did, I didn't care very much about improving my playing strength. I just liked it and wanted to learn about it. My results otb got worse.

Thank you! Meanwhile I suspect that these "delay the contact" openings create the warm and fuzzy feeling of having played the opening well when in fact it was just played slowly and without losing material, which adds to their popularity. Good thing: even if you go for open 1.e4 games, your KIA may be useful to occasionally fill gaps in your e4 repertoire. And if you don't care about results, it's fun anyway.

Is there a typo in there? Is this what you meant to write?

"You can play a KIA/Vienna against ...e5 but it isn't as strong as against the CK or French. Don't think you can play it against 1... d5."

If so, I think that that is more or less what the late GM Evans wrote in his book many decades ago. As I recall, he told his readers that it is necessary to forget about the KIA after 1 e4 d5. After 1 e4 e5, I think his idea was for the reader to play some sort of Glek-thing, although I don't think he used the name, Glek. I believe that IM pfren recently told us that the Glek stuff is not really very KIAy. (He, of course, put it somewhat better than that.)

The King's Indian Attack is sometimes suggested as a sort of quick-fix opening solution for near-beginners, but notice the reservations that IM Watson had while mentioning the idea.
"... For players with very limited experience, I recommend using openings in which the play can be clarified at an early stage, often with a degree of simplification. To accomplish this safely will take a little study, because you will have to get used to playing wiith open lines for both sides' pieces, but you can't eliminate risk entirely in the opening anyway. ... teachers all over the world suggest that inexperienced players begin with 1 e4. ... You will undoubtedly see the reply 1 ... e5 most often when playing at or near a beginner's level, ... After 2 Nf3, 2 ... Nc6 will occur in the bulk of your games. ... I recommend taking up the classical and instructive move 3 Bc4 at an early stage. Then, against 3 ... Bc5, it's thematic to try to establish the ideal centre by 4 c3 and 5 d4; after that, things can get complicated enough that you need to take a look at some theory and learn the basics; ... Of course, you can also play 1 d4 ... A solid and more-or-less universal set-up is 2 Nf3 and 3 Bf4, followed in most cases by 4 e3, 5 Be2 and 6 0-0. I'd rather see my students fight their way through open positions instead; however, if you're not getting out of the opening alive after 1 e4, this method of playing 1 d4 deserves consideration. ... a commonly suggested 'easy' repertoire for White with 1 Nf3 and the King's indian Attack ... doesn't lead to an open game or one with a clear plan for White. Furthermore, it encourages mechanical play. Similarly, teachers sometimes recommend the Colle System ..., which can also be played too automatically, and usually doesn't lead to an open position. For true beginners, the King's Indian Attack and Colle System have the benefit of offering a safe position that nearly guarantees passage to some kind of playable middlegame; they may be a reasonable alternative if other openings are too intimidating. But having gained even a small amount of experience, you really should switch to more open and less automatic play." - IM John Watson in a section of his 2010 book, Mastering the Chess Openings, Volume 4

It seems to me that, while not approving, IM Watson was somewhat open to the idea of a near-beginner choosing the KIA. If one makes that choice, it might be a good idea to play over some of the games in a book like The King's Indian Attack: Move by Move by Grandmaster Neil McDonald (2014).
https://www.newinchess.com/media/wysiwyg/product_pdf/7277.pdf

I don't think that it considers 1 e4 e5 2 Nc3 Nf6 3 g3. For that, it might be necessary to try Vienna Game by Gary Lane (2000).

https://web.archive.org/web/20140627005622/http://www.chesscafe.com/text/hansen19.pdf

Not sure what conclusion you draw from that. IM Watson sounds convincing to me in his preference for near-beginners going for something like 1 e4 e5 2 Nf3 Nc6 3 Bc4, but he seems to recognize that a near-beginner might understandably choose KIA as a way to get to "some kind of playable middlegame" even without "knowing what one is doing".

What pfren said is totally the truth.  You can't use it systematically.

For example, in the KIA vs French (1.e4 e6 2.d3 d5 3.Nd2 etc), White almost always goes for a raging Kingside attack.

However, in the KIA vs Sicilian (1.e4 c5 2.Nf3 e6 3.d3 and Black doesn't play ...d5, the idea is almost always to play for d4 (i.e. c3 and d4).

Just one of numerous differences, and that analysis is literally at the 10,000 foot level.  It's actually very theoretical.

"... For true beginners, the King's Indian Attack and Colle System have the benefit of offering a safe position that nearly guarantees passage to some kind of playable middlegame; they may be a reasonable alternative if other openings are too intimidating. But having gained even a small amount of experience, you really should switch to more open and less automatic play." - IM John Watson (2010)