What do?
Villain has shown that although he is tight, he is capable in bluffing in some spots, although so far it was mainly in weird spots (like he'd bluff-check/raise and barrel off his stack on a paired board with the nut flush draw).

Not a big hand but still

Poker Stars $10.00 Pot Limit Omaha Hi - 6 players - View hand 2716074
DeucesCracked Poker Videos Hand History Converter

BTN: $9.65 - VPIP: 37, PFR: 22, 3B: 10, AF: 1.9, Hands: 346
SB: $15.72 - VPIP: 51, PFR: 12, 3B: 0, AF: 1.8, Hands: 51
BB: $8.40 - VPIP: 13, PFR: 1, 3B: 1, AF: 1.0, Hands: 366
UTG: $14.78 - VPIP: 46, PFR: 21, 3B: 7, AF: 1.3, Hands: 135
MP: $23.69 - VPIP: 27, PFR: 14, 3B: 3, AF: 3.1, Hands: 1594
Hero (CO): $40.70

Pre Flop: ($0.15) Hero is CO with 9 A Q 6
1 fold, MP raises to $0.25, Hero raises to $0.90, 3 folds, MP calls $0.65

Flop: ($1.95) 3 4 Q (2 players)
MP checks, Hero bets $1.40, MP calls $1.40

Turn: ($4.75) K (2 players)
MP checks, Hero checks

River: ($4.75) 6 (2 players)
MP bets $2.50, Hero ?

i think the turn card is pretty good for barreling. b/f turn and decide if we want to bluff r. this river i think we just fold. villain can be valuebetting soo much here... we pretty much always have only a 1 pair hand when we get to the river like this.

we rivered 2p

^ oops. yeah misread hh. my bad, i was browsing with my phone at the time.

umm... well that makes it tougher obv.

well MP has very little straights here given how tight he is PF, albeit some weird KK75ds things and ds rundowns fit in there but that's about it

really dunno. has to be one of dem gut feelings spots. as i don't have any grasp on how our opponent plays rivers/what kind of sizings he uses for value it's hard to say. like what does he call the flop with and now decides to bluff with?

sizings looks a lot like value to me... like KQ or KK

i guess we could beat something like a lone Q that he decided to turn into a bluff when he didn't hit 2p.

if he actually had a decent wrap OTF i'd expect him to x/raise due to the information you provided so again, not expecting to see a lot of straights here

in conlusion it's definitely not a horrible fold nor call. maybe just continue folding these spots as a player pool adjustment until villain gives us reason not to.

now i'm curious tho. results pls.

I folded and he mucked for results... Didn't feel like bluff-catching here