1/2 NL. 9 max.
We overlimped 2s2h UTG+1, and end up 8 players on the flop.

Flop Kh7h2c. Checked to me I bet 20$ into 18, get called from reg on BU and whale on SB. SB has all range - 5% he would raise, BU is quite tight and aggressive, I believe he would raise 66+, ATo+, KJo+ QJo+, 65s+ any suited broadway and any suited ace.

Turn Ts. I bet 75 into 78, BU quickly calls, whale folds.

River 9d. Pot 228$, BU has 275$ left I cover. After snap calling potsize bet on the turn, I think he's range is pretty much 2 pairs and flush draws(but I assume all suited Ax he raise preflop), Top 2 he bets himself. So if we check we loose value from K7s 3 combos(I don't think he overlimps K7o on BU), and 1 combo K2s(which he might fold) and give a chance to bet FD with no SD.
BU has a bad session, was down few buyins already, however I don't have an info how aggressive he's on the river.

Check or bet river?

you led into 8 players and then psb barreled turn
doubt he'll bluff missed flush draw into you if you check so bet


then V drags pot with 77

I'd definitely bet. You've shown a good amount of strength and aggression already; don't think you can expect a bluff from a flush draw. Jam and hope he calls with 2-pair or even just a K if he's bad enough; he's called 2 pot sized bets so far, decent chance he'll call another big bet.