Differences of ratings between lichess and chess.com?

On chess.com my blitz rating is 1700 and I am 96,9% in percentile.

On lichess I am 2150, but only 89,9% percentile.

Does that mean the pool on lichess is stronger?

Lichess to FIDE Elo Rating Conversion – Singapore Maths Tuition

yes, but I wouldn't worry about percentiles. The chess.com pool is notoriously low rated, it could have a lot of old and inactive accounts. They want people to think they're in the top 3% by being 1700 so that's why they do that. Anything that compliments people about themselves will cause them to come back. Of course they would like to inflate ratings as well, but they don't want to come off as a bit of a joke, so that is why they're only a little inflated from the FIDE and no more. Hikaru has hit 3300 blitz so it's clear there is still rampant inflation, at least at the high levels. 

Lichess is more generous in giving higher ratings 

https://chessgoals.com/rating-comparison/

So if my year rating goal is to get to 1600 and I'm currently around 1400 does this mean I should join Lichess and boom, 1600? :D

I don't know, but I do feel and experienced that everytime I played/won a lot of games in lichess, the ratings goes up much faster than chess.com

I guess you would be 1600 there, but that doesn’t really means you got any better.

I am 1400 on lichess and 1200 on chess.com. But I think in the opening lichess players are better but overall in technique, I think chess.com is good

Chess_com rating is more precise because it doesn't start with the meaning 1500 which is incorrect in its essence. 

You know Elo doesn't show which aspects of chess anyone is good at. It is just calculus used to determine an expected win loss rate against similar banded players. One pool rating has no bearing on another as groups stratify. If you only play one group of players and not another group your score will reflect the outcomes of your games. So your strengths and weaknesses are going to give different scores in different pools. Hikaru isnt any stronger or weaker in real life to otb or another platform but he will get different scores. As long as you can see progress and improvements to your game regarding the types of errors or critical moves then be thankful.