Party 15/30 - value bet with AK unimproved?

[Senor Choppy]

I haven't played at this limit much and am still trying to cut out a lot of leaks, especially in hands like this where I'm not used to deciding how far to go with just a good ace. The game is the typical 15/30 on Party.

Middle position player has open raised, folded to me in a blind and I 3-bet. Heads up to the flop.

Flop is t 9 x. I bet and my opponent quickly calls.

Turn is a blank. I bet and he calls.

River another blank. I bet and he calls.

My thinking on the flop after he calls is that he has something like 77 or Ax. On the river I'm 95% sure I'm getting called so I'm betting for value. A small pocket pair is going to bet if checked to, and a worse ace is going to check so I feel like I'm gaining a bet the small % of the time I'm ahead, losing the same amount if I check/call (which I planned on doing).

My opponent had a9o, which I think he played the same as he would 77 so my read was ok.

I felt good about my play at the time but I've rethought. I didn't think a raise was that much of a possibility, but now I think tt or 99 might wait and pop me on the river (unlikely but possible). I also think I lose out on a possible bet by qj/kj/kq if I bet the river. And if I get raised by those hands, or any other hands he might bluff with, I just cost myself the entire pot.

Commments on the flop through the river would be appreciated.