[SH] NL50 QJo

Poker Stars, $0.25/$0.50 No Limit Hold'em Cash, 6 Players

UTG: $20 (40 bb)
MP: $35.36 (70.7 bb)
CO: $55.20 (110.4 bb)
BTN: $40.43 (80.9 bb)
SB: $50.25 (100.5 bb)
Hero (BB): $55.47 (110.9 bb)

Preflop: Hero is BB with Q J
4 folds, SB raises to $1.50, Hero calls $1

Flop: ($3) 2 9 9 (2 players)
SB bets $2, Hero calls $2

Turn: ($7) 2 (2 players)
SB checks, Hero bets $5, SB calls $5

River: ($17) T (2 players)
SB checks, Hero bets $20,

SB 25/21
SB steal 40%
postflop samples are small

I assumed that he vbets turn with his overpairs most of the time, so his ch/call range could mainly contain weak hands like 33-88, Ax.
What do you think about overbetting river? I represent a thin range with 9x, but he is in a tough spot with hands like AQ or 33...