Still PLO25

The flop is one of those spots where you don't have to worry about being balanced. It's a draw heavy board so go ahead and bet full pot and stack off if raised.

The turn is certainly a scary card but if villain had a straight here, he probably donks it a lot of the time rather than offering you a free card (since there is both a flush draw and a higher straight draw out there).

River is super sick. By all accounts your opponent is passive and the only hand I can possibly imagine I am losing to on this river is something like T87x where villain had an outside straight draw on the flop and backdoored in to a full house.

I really don't see how a set of nines can possibly be in his range the way he played the hand but likewise your read on villain is that he is a super passive nit who only bets the nuts so maybe you can make a sick laydown here.

I definitely don't see him ever betting a busted draw on the river but I am not sure I am good enough to make this fold even though I probably suspect I am not good here as T9 is certainly possible.