$400 effective

BB: 30s, tight passive, hasn't played many hands. Don't remember a raise.
UTG/hero: 99. TAG

Hero raises $20, LP and blinds call

Board ($75): T83/2/6 all
Checked all the way through to hero who bets $25 with one player left to act. Folds to BB who c/r to $60

1. Do you VB riv in this spot given the (non) action?
2. Do we call this raise? Did BB really check back the nuts OTR or even the K?

Tight passive player check raised you on the river... Fold.

Not value betting this river because I don't think worse calls very often.

Well I've seen enough times where someone in my spot bluffs trying to steal the pot, only to get called down by a baby card of the flush suit. Or a player bets with that baby card and gets called by air that was hoping to chop the pot.

No and No. The 7,5, or 4 of spades never call. It's really more of a bluff hoping J+ will fold. Q+ never fold. A tight passive isn't raising with worse or bluffing.

I would cbet this monochrome flop. I expect a lot of folds and shutdown after the fourth spade.

Preflop: Good.

Flop: Bet $55. You need to bet enough to protect your hand against flush draws. You are less likely than usual to have your c-bet bluffed (by anything other than the A) because your range includes big pairs and bigs, so if your c-bet gets raised you can safely muck.

Turn: As played, Check. Even though you have a flush betting is essentially a bluff against non-calling stations and your hand has showdown value.

River: By this point your bet is fine, you might as well try to get some value out of your flush. Despite the price you're getting, fold after the check/raise. The BB very well could have a large that he was waiting to check/raise with assuming you'd eventually bet again. Against a more aggressive player, this is a call because it's not a bad spot to bluff, but tight/passive players tend not to take advantage of situations like this.

Just my opinion...