PFR'er is 26/7 over 87 hands. BB is 18/11 over 27 hands. Do you flat call pre-flop or re-raise? What's your play and plan on the flop?

Party Poker No-Limit Hold'em, $ BB (10 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG+2 ($136.64)
MP1 ($168.92)
MP2 ($98.59)
MP3 ($75)
CO ($153.78)
Button ($95.80)
Hero ($99)
BB ($64.30)
UTG ($106.83)
UTG+1 ($51.21)

Preflop: Hero is SB with A, K. Hero posts a blind of $0.50.
5 folds, MP3 raises to $5, 2 folds, Hero (poster) calls $4.50, BB calls $4.

Flop: ($15) 9, Q, A (3 players)
Hero ???