Set on straight draw board with super passive and uber tight

I think my line here was fine, just checking:

2-4, 6 handed.

I've been raising a lot here preflop, just baiting some tight players to open up against me. I've been kinduv rocky on the flop; opponents have been hitting hands against me and I'm a bit rattled. About 40 minutes into play. BB is super passive, he's been calling me on the flop and turn all [censored] night. He only bets out when he has something. So far, I've seen him call raises with Q9o, 85o, and A6o all off the blind from all different raisers. UTG is super tight.

UTG raises to 12
Hero with 99 calls off button
BB calls

Flop: 5 9 6 r
Pot: 38

UTG bets 15
Hero raises to 50.

My goal was to knock out passive while keeping tighty in with 1010 or higher. Analysis?