Can you fold a set?

Party Poker No-Limit Hold'em, $ Hero (6 max, 10 handed) FTR converter on zerodivide.cx

UTG+2 ($85.70)
MP1 ($97.79)
MP2 ($40.15)
MP3 ($194.01)
CO ($164.88)
Button ($212.82)
SB ($41.35)
Hero ($218.07)
UTG ($85.50)
UTG+1 ($103.50)

Preflop: Hero is BB with 9s, 9h. SB posts a blind of $0.50.
4 folds, MP2 calls $1, 1 fold, CO calls $1, Button raises to $4, 1 fold, Hero calls $3, MP2 calls $3, CO calls $3.

Flop: ($16.50) 5d, Kd, 9c (4 players)
Hero bets $10, MP2 folds, CO calls $10, Button folds.

Turn: ($36.50) Jd (2 players)
Hero bets $30, CO calls $150.88 (All-In)

sorry for not converting the first time

edit: i was about 90% sure he had a FLUSH so was I justified in calling in attempt to fill up? were my pot odds wrong? thx