Villian seems loose passive preflop. Don't have much info on post-flop play.

Party Poker No-Limit Hold'em, $ BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($24.65)
SB ($47.91)
BB ($9.90)
UTG ($20.54)
MP ($4.80)
CO ($25)

Preflop: Hero is Button with T, K. SB posts a blind of $0.10.
2 folds, CO calls $0.25, Hero raises to $0.75, 2 folds, CO calls $0.50.

Flop: ($1.85) Q, 6, 9 (2 players)
CO checks, Hero bets $1, CO calls $1.

Turn: ($3.85) J (2 players)
CO checks, Hero bets $3, CO calls $3.

River: ($9.85) K (2 players)
CO bets $2, Hero ???

Do you just call (assuming he also likely just has a T, and may even have AT)? Or do you raise (hoping he just made something like two pair or trips, or is just trying to bluff repping a straight)?