6-handed, we're straddling every hand. $1000 eff. I'm in UTG straddle with 3♦ 2♥

Loose passive fish limps OTB, SB fish completes, BB completes, I check.

Flop: 6♣ 5♣ 9♠ Pot $40 Checks around
Turn: 4♦ Pot $40 SB leads $35, BB makes it $85

BB is a fairly competent player, quite aware of hand strength. I'm kind of ruling out 87 because V is competent enough to fire that OTF, especially with the flush draw there and for many other reasons. I'm not sure how often 73 is in BB's range there. I think two pairs and PPs are in V's range here.

Given all this, how do we proceed and what's the plan for the river?