What to do if an opponent transposes into a King's Indian?

So I was just playing a match and after a few moves my opponent ended up fianchetto'ing his dark square bishop and then castling short. I wasn't sure how to proceed and ended up just trying to play the standard London. This didn't end up well and I went on to lose this match. How should I have proceeded?

Here's the match I am talking about: https://lichess.org/BTftpOWZ/

@afgator58

In this case I think 9.Bg3 was not needed. Instead maybe you can rush your h-pawn to h5 and sacrifice the exchange on h5. With your well placed pieces you should be able to get a winning attack out of that.

In black's fianchetto systems, usually you want to keep your dark squared bishop to exchange for black's bishop. So maybe you can play 12.Bf2! Keeping the bishop for an eventual exchange later, and making the knight on h5 look strange.

What is your point of 17.Qh3? In my opinion you should instead bring some more of your pieces over to the kingside, say Rf3 or Nf3. The attack is going to be harder here because black has the dark squared bishop, but still if you can get more pieces over there then you should be pretty good. (Plus if you can get your knight back to f3 then he prevents black queen from coming to g5)

These are just my thoughts- you should ask some other people their thoughts too.

Happy Checkmating!

@FunnyAnimatorJimTV

Thanks for the advice. After going through the mistakes made in the London lessons I realized that saving my dark square bishop for the trade is probably the most important part of an attack on the kingside.

When ever your opponent fianchetto's his black bishop. Immediately go for an exchange by your black bishop with the help of queen.
Here your opponent waited for you to move Nd2, and when when you did that he pushed g6 you noticed that? Otherwise you will put queen on d2 and push e4 and make a bishop queen battery to challenge black bishop.

@Sumit_Garg I see what you mean when you say that he waited to expose his fianchetto plan until after I went Nd2. But what should I have done instead of Nd2, there isn't really a better position for that knight other than d2?

Dear @afgator58

For instance, you can play Nf3 and c3 first. However I don't think that you should worry about black placing his bishop on g7 against the London. It is just looking at your d4-c3-b2 pawn chain. After you finished development you can try to push e4. I think that in all lines white has a clear iniative.

Greetings,
Funbeat