should I have reraised or was i right to just call it down?

Because he was in the BB... I really wasn't sure what he could have..

Ultimate Bet 0.25/0.50 Hold'em (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Preflop: Hero is SB with K, K.
UTG+1 calls, 1 fold, MP2 calls, 3 folds, Hero raises, BB calls, UTG+1 calls, MP2 calls.

Flop: (8 SB) 3, 3, 6 (5 players)
Hero bets, BB calls, UTG+1 folds, MP2 folds.

Turn: (5 BB) J (3 players)
Hero bets, BB raises, Hero calls.

River: (9 BB) 9 (3 players)
Hero checks, BB bets, Hero calls.

Final Pot: 11 BB