NL25 - tough spot with 99 - bottom straight

[reemas]

this hand has me confused after the flop comes down.
after 45 hands, opponent is 38/19/1.24

Poker Stars, $0.10/$0.25 NL Hold'em Cash Game, 5 Players
LeggoPoker.com - Hand History Converter

UTG: $14.20
CO: $25.15
BTN: $22.95
SB: $38.95
Hero (BB): $21.95

Pre-Flop: 9[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/heart.gif[/img] dealt to Hero (BB)
2 folds, BTN calls $0.25, SB calls $0.15, <font color="red">Hero raises to $1.50</font>, BTN calls $1.25, SB folds

Flop: ($3.25) T[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/spade.gif[/img] Q[img]/images/graemlins/club.gif[/img] (2 Players)
Hero checks, BTN checks

Turn: ($3.25) J[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">Hero bets $2</font>, <font color="red">BTN raises to $4</font>, Hero ?