Flush made with low cards on flop against LAG

[DrSnow]

Villian has been calling every single raise I have done so far and has been playing a lot of suited cards/connectors both raising/calling raises/limping.
I've been playing pretty tight and has laid down a lot of hands post flop. Was waiting for an opportunity to stack him and here it comes. Found it strange though that he would make this move on a board like this unless he has a better flush.
Should I stack him instead of folding?

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

Button ($13.45)
SB ($3.20)
BB ($26.85)
Hero ($27.95)

Preflop: Hero is UTG with 4, 5.
Hero calls $0.25, [color=#CC3333]Button raises to $0.5</font>, SB calls $0.40, BB calls $0.25, Hero calls $0.25.

Flop: ($2) T, 9, 8 [color=#0000FF](4 players)</font>
SB checks, BB checks, [color=#CC3333]Hero bets $0.75</font>, Button calls $0.75, SB folds, BB folds.

Turn: ($3.50) 8 [color=#0000FF](2 players)</font>
[color=#CC3333]Hero bets $2</font>, [color=#CC3333]Button raises to $6</font>, Hero folds.

Final Pot: $11.50