I think this is played fine. If you are never raising T9s there in EP you are playing too tight IMO. It helps vary your EP raising range when you end up showing it down to people. Not saying do it every time, but it's fine. And if you are good post flop against a bad table then you are extra fine!
Flop/Turn/River played just fine IMO.
You said villain was an aggro regular, but does he have ANY history at all with you to know you are usually "super tight in EP"? If he does know this and is a good player as you described him then even he will slow down at that point.
You just haven't given enough information here, or don't know enough information yourself, to make a great river decision.
However, with the third player in the pot he would have raised a made hand...sets, 2 pair, straights. The cold call by the BB on the flop makes this an easy turn raise with any hand like that with the flush draw out there. You can discount those hands.
This smells to me like one of three things...
A9
Pair 88, TT, or JJ he is turning into a bluff (If he is aware of your "super tight pre image)
A missed flush draw, possibly A-2h that turned into 2 pair. I don't think he bets this size with Axh one pair, instead bets for value or even possibly checks behind, although I'd hedge a bit on this when doing my head math as you haven't played enough with him to be sure.
You're going to have to call here and pay him off getting 2:1. Sounded like he turned over the winner on you for a big pot, so just say nice hand and move on. Don't be result oriented