I think that final call depends alot on how big the stack sizes are compared to the pot. I wouldnt figure my A9 to be ahead here much after a call on the flop and turn and then the third flush card on top of that but if there was only a little left that he pushed then i dont think its tooooo bad a river call. If he went in for more than the size of the pot though i think its pretty terrible.
I fold preflop or maybe try a raise + continuation bet as a steal.
If he calls my flop bet i want a cheap showdown or fold