What to do?

Im sitting on UTG with AA. I throw in a raise of bbx3 (blinds 100-200) my stack is around 5,600 and I get one caller. The callers stack is aroud 5,600 too. A little bit more.

Flop comes K-K-9 rainbow and I raise with a pot size bet here. He says "I raise whatever you have left" which is around 3,500 there so I got 15-17 BB if I fold which is no way bad for me.

Fold or call? My read on him is that he overplays all of his cards especially if he is sitting on A with a nice kicker but what I am most worried about here is either KQ or 99.