Full Tilt - micro NL - Holdem - 7 players
Hand converted by PokerTracker 4

BTN: 72.5 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: -, Hands: 3)
SB: 179 BB (VPIP: 10.00, PFR: 5.00, 3Bet Preflop: 0.00, Hands: 20)
Hero (BB): 100 BB
UTG: 430 BB (VPIP: 17.39, PFR: 8.70, 3Bet Preflop: 0.00, Hands: 23)
UTG+1: 100 BB (VPIP: 14.71, PFR: 8.82, 3Bet Preflop: 6.67, Hands: 34)
MP: 100 BB (VPIP: 13.21, PFR: 9.49, 3Bet Preflop: 2.19, Hands: 1,032)
CO: 56 BB

SB posts SB 0.5 BB, Hero posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has 4 9

fold, fold, fold, fold, fold, SB raises to 2 BB, Hero raises to 5 BB, SB calls 3 BB

Flop: (10 BB, 2 players) 7 2 J
SB checks, Hero bets 4 BB, SB calls 4 BB

Turn: (18 BB, 2 players) 6
SB checks, Hero checks

River: (18 BB, 2 players) Q
SB checks, Hero bets 9 BB
Fold pre, check flop, check turn (that's how it should go right?)
Now, what do you think about this bet otr? I felt weakness from our opponent and was pretty confident to make a bet here it didn't seem like he caught up something also he looked like a passive player -

pls fold more often.

I'm not sure you can tell that SB is passive with only 20 hands.

Also, if someone is passive, You can't really bluff him, as he will call loosely. Just check when you miss and raise when you hit.

No reason to 3b pre. You can 3b bluff with better hands that actually have some playability postflop.