SB is 39/9/2.1. What is the proper way to play this?

PokerStars No-Limit Hold'em, $0.50 BB (8 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

MP2 ($9.25)
CO ($10)
Button ($65.40)
SB ($117.40)
Hero (BB) ($50)
UTG ($40.95)
UTG+1 ($9.25)
MP1 ($26.75)

Preflop: Hero is BB with 5, 7
2 folds, MP1 raises to $1, 1 fold, CO calls $1, 1 fold, SB calls $0.75, Hero calls $0.50

Flop: ($4) 5, 2, 9 (4 players)
SB checks, Hero bets $2, 1 fold, CO calls $2, SB raises to $8,