Live 1/3 PL Top two, scary board.
 

9 handed. Game is playing extremely passive preflop(tons of limping, not a lot of raises), but there haven't been many pots won without a showdown. Usually 4-7 players to a flop.

Dealt KQ o in the CO. 4 players to the flop, UTG, UTG+1, me and the button. I want to say it was $7, but don't remember the exact action, could've been limped.

Flop comes down Ks Qs 10x. UTG bets $10, call, I make it $30. Fold, 2 calls.

Turn comes 9s completing the flush and straight draws. check, check. I have a feeling I'm being slow played by one or both, so I check behind.

River is a brick. Check, check. I don't think i get a call from anything I beat, so I check. Thoughts? Too passive on my part?