Live 3/6 Flopped Set. Who raises the river?

[PokrLikeItsProse]

Live 3/6 hand. I've just sat down and folded a couple of orbits and this is my first hand. UTG villain is aggressive. Unlike most 3/6 players, he raises preflop with decent pocket pairs, big aces, and suited broadway cards, but doesn't seem to raise junk hands preflop. He occasionally will straddle, though. He seems observant enough to know that I am tight, but I am not sure if he has played enough with me to make that read. I am fairly certain that he will raise preflop from early position with AT and won't with A8. I am not sure how far he is willing to go with two pair or if he is capable of checking the flop with TPTK.



Preflop:
Full table. UTG raises. MP1 calls. I call in MP3 with 99. BB calls. I'm a bit shocked it was only four-handed going to the flop.

Flop: A98r suits irrelevent
Checked to me, I bet, BB folds, UTG calls, MP1 folds.

Turn: K bringing a two flush
UTG checks. I bet. UTG check-raises. I three-bet. UTG caps.

River: 2 not completing the flush
UTG bets. I call.

Given my read, is my call on the river the right play?