Id probably call. He doesnt know you have a flush.

Surely he would raise the turn with a draw heavy board if that 9 made him two pair.
Also surely hes not stupid enough to give away a free heart if he flopped trips.
Id be more worried about a suited ace as it looks like hes drawing.

I think you where beat by an ace high flush here, but a lot of times your seeing a 9 here, a worse flush or someone make a move when a super scare card like that drops.
I like betting my nut flush draws because of how often people bluff me when i hit it.