5NL FR flopped set 3way OOP

UTG+1 is 14/12 over 44 hands, 100%cbet (3 hands), 5AF, 31%AggFreq
CO is 16/5 over 37 hands, 4AF, 36% AggFreq

I check with the intention of calling a bet, as the flop is relatively dry.

After the flop action, I'd put UTG+1 on 99-QQ,AdKd,AdQd and CO on 99+,33,Ad9d+,KdJd+,QdJd... maybe more AdsXd.

Not sure what's best after CO's raise. Get it in or flat? I would lean towards shoving, as CO is showing quite a lot of strength, but maybe flatting would give a chance to UTG+1 to do the shoving for me? There is also a non-zero chance that they both fold if I shove.

Full Tilt No-Limit Hold'em, $0.05 BB (8 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

saw flop

UTG+1 ($5.53)
MP1 ($5.07)
MP2 ($12.40)
CO ($6.08)
Button ($6.12)
Hero (SB) ($5)
BB ($5.18)
UTG ($5)

Preflop: Hero is SB with 5, 5
1 fold, UTG+1 bets $0.20, 2 folds, CO calls $0.20, 1 fold, Hero calls $0.18, 1 fold

Flop: ($0.65) 9, 3, 5 (3 players)
Hero checks, UTG+1 bets $0.65, CO raises to $1.50

Hero?