Betting with draws.. line check

Villain is unknown..

PokerRoom No-Limit Hold'em, $0.25 BB (4 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($36.45)
UTG ($23.35)
Button ($17.85)
SB ($14.65)

Preflop: Hero is BB with 5, A.
UTG calls $0.25, 1 fold, SB completes, Hero checks.

Flop: ($1) 6, 4, T (3 players)
SB checks, Hero bets $0.5, UTG raises to $1, SB folds, Hero calls $0.50.

Turn: ($3) 7 (2 players)
Hero bets $2, UTG calls $2.

River: ($7) 9 (2 players)
Hero bets $4

I let villain bet the turn? if he checks behind, no big deal...

I think on the turn and river you are only folding a bluff, which is not likely from the flop minraise.