Check it back unless he is especially retarded.

Or I am

Easy check back :) flush draws and backdoor straights got there, even AA got there if he was calling with that. He's not calling with worse

I'd go bigger OTT, check back river. too thin for a valuebet.

Agree, I bet 99c on the turn and I check back the river.

With his stack you would have heard about 44, 66 and KT etc by the turn. If for some reason he did elect to play these this passively then he got a get out of jail free card on the river.

Note that because the Ac came on the river, if he was drawing to a flush, he was calling (in his mind at least) with a non-nut flush draw. It's something to think about and perhaps make a note on him and also note that he didn't lead the river with a pretty low SPR.

He's only got 1/2 a pot size bet behind, so no point trying to turn your hand into a bluff here. He just isn't folding a flush. He was also short stacked to begin the hand, potentially indicating so weaker.

I would also note that once the T drops on the turn all river cards will put a straight on the board making it a bit harder to bet the river.