10NL - 99 Line check

[Gospy]

Poker Stars, $0.05/$0.10 NL Hold'em Cash Game, 6 Players
LegoPoker Hand History Converter

Hero (CO): $10.55
BTN: $8.90
SB: $3.70
BB: $3.30
UTG: $11.10
MP: $25.65

Pre-Flop: 9[img]/images/graemlins/spade.gif[/img] 9[img]/images/graemlins/club.gif[/img] dealt to Hero (CO)
UTG folds, MP calls $0.10, <font color="red">Hero raises to $0.40</font>, BTN calls $0.40, 3 folds

Flop: ($1.05) K[img]/images/graemlins/spade.gif[/img] 4[img]/images/graemlins/club.gif[/img] 4[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">Hero bets $0.85</font>, BTN calls $0.85

Turn: ($2.75) 6[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">Hero bets $1.75</font>, BTN calls $1.75

River: ($6.25) 2[img]/images/graemlins/diamond.gif[/img] (2 Players)
Hero checks, BTN checks

I figured since board was paired, it was alright to double barrel here. Is this ok?