Slow Played Set

PokerStars - $0.05 NL FAST - Holdem - 9 players
Hand converted by PokerTracker 4

BTN: 102 BB
SB: 72.4 BB
Hero (BB): 100 BB
UTG: 104.2 BB
UTG+1: 50 BB
UTG+2: 47.2 BB
MP: 171.4 BB
MP+1: 230.8 BB (VPIP: 33.33, PFR: 33.33, 3Bet Preflop: 0.00, Hands: 3)
CO: 532.8 BB (VPIP: 5.88, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 17)

SB posts SB 0.4 BB, Hero posts BB 1 BB

Pre Flop: (pot: 1.4 BB) Hero has 4:spade: 4:diamond:

fold, fold, fold, fold, MP+1 raises to 4 BB, CO calls 4 BB, fold, fold, Hero calls 3 BB

Flop: (12.4 BB, 3 players) 9:club: 4:heart: Q:spade:
Hero checks, MP+1 bets 8 BB, CO calls 8 BB, Hero calls 8 BB

Turn: (36.4 BB, 3 players) 3:club:
Hero checks, MP+1 checks, CO checks

River: (36.4 BB, 3 players) A:diamond:
Hero bets 26 BB, fold, CO raises to 87 BB, Hero raises to 88 BB and is all-in, CO calls 1 BB

This is zoom. Obv it went all wrong. Can I have some thoughts on slow playing in these circumstances. Should I ever slow play 3 handed?

With all 3 in the hand on the turn should I have led?

Should I have folded to the 2 bet on the river? There are no straights or flushes here. I thought it more likely I would be facing a 2 pair hand than a higher set. On the other hand zoom is notoriously nitty and a river re-raise is usually very strong.

OTF: c/r, trying to get it in and play for stacks
OTT: leading out and if not jamming, sizing for a river jam
OTR: No change.

as played, it's fine. You've severely under-repped your hand, and 52 is the only straight with no flush on board. If CO has a higher set, he successfully trapped you, and oh well, since he's not repped AA, so he would have had you beat the whole time, and you were playing for stacks OTF, so what can you do.

^^ what he said

I don't think we'd be bluffing a whole lot in this spot, but like lol, it's 5nl, and you're OOP to two unknowns. Just c/r and see them show down all sorts of ridiculous shit. The c/x flop, check turn line is relying too much on your opponents being aggressive.