hand 3... could villian have something like 9T or KT hearts?

If you are raising high cards, then the only hand that hit you was AJ or 2 hearts. Your c-bet doesn't really mean much to him... the Q has to scare you if you have AJ or TT or something. He is repping AQ or KQ - and he might have it, to. he could have TP + a draw as well.

I think the crux is - if you flat call - will he put you on 2 hearts and fold if you river the flush? It's disasterous to call and then not stack him if you hit your 9 outer.

Nice donk bet by villian, I wouldn't be surprised if he has a clue.