Handicap: How much?

How much of a handicap is playing a3, b3, c3, d3, e3, f3, g3, h3, a4 as your first 9 moves?

My opponent didn't threaten me early but I had struggles to defend my position in the middle game.

What's your strength level?  How strong of a player are you and how strong is your opponent?

If you're a "beginner" or a weak player (and if you're playing these nine moves then you probably are, at least by my standards) and if your opponent is also a beginner/weak player, then it's not much of a handicap.  Both of you will either win or lose the game later, with other mistakes you make.

The stronger you are, and maybe more importantly, the stronger your opponent is, the more of a handicap it is.  I wish all of my over-the-board opponents in my tournaments would play these nine moves!

I am currently about 1200-1250 in 10 minute games online on this website. My friend who I play against hasn't beaten me in like 10-20 games. He doesn't want material handicap though, so I tend to play less known openings. This game was just for kicks though.

My friend does blunder rather frequently (like 0.3-0.5 times per game) but we allow takebacks if it totally messes up the game. Blundering the exchange or a pawn or two is less frequently taken back however.