$2 NLHE 6-max: pocket 3's flop oesd... how to play?

pokerstars - $0.02 NL FAST (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4: http://www.pokertracker.com

BTN: 282 BB (VPIP: 10.00, PFR: 10.00, 3Bet Preflop: 0.00, hands: 10)
SB: 49 BB (VPIP: 50.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 4)
BB: 217 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 39)
UTG: 298 BB
MP: 115.5 BB (VPIP: 26.67, PFR: 26.67, 3Bet Preflop: 12.50, Hands: 16)
Hero (CO): 150.5 BB

SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has 3c 3s
UTG raises to 2 BB, fold, Hero calls 2 BB, BTN calls 2 BB, SB calls 1.5 BB, fold

Flop : (9 BB, 4 players) 4s 6d 5d
SB checks, UTG bets 1 BB, Hero raises to 6 BB, fold, fold, UTG raises to 11 BB, Hero calls 5 BB

Turn : (31 BB, 2 players) 8h
UTG checks, Hero checks

River : (31 BB, 2 players) 9h
UTG checks, Hero checks

UTG shows As Ks (High Card, Ace) (Pre 49%, Flop 27%, Turn 18%)
Hero shows 3c 3s (One Pair, Threes) (Pre 51%, Flop 73%, Turn 82%)
Hero wins 30 BB

I like your line here, nice re raise on flop to get what seems like a week bet to fold. Then the flat. Also I like the check behind, pots already 60c and you hold an under pair. I am check folding in this position as it was 4 way pre and he can hold a 1 pair type hand. And there is little point in betting river, you have some show down value and if he re raises here it puts you in tough spot. Overall I would say well played! (Especially with no Info on him)

Call 1 BB, fold if someone reraises. You made the pot bigger for no reason. You have and underpair and a very weak draw and you could be drawing dead already.

Small hand, small pot, agree no need to raise.