NL100 KJs flop set 400bb deep

Poker Stars, $0.50/$1 No Limit Hold'em Cash, 6 Players

BTN: $62.09 (62.1 bb)
SB: $233.29 (233.3 bb)
Hero (BB): $391.75 (391.8 bb)
UTG: $132.15 (132.2 bb)
MP: $159.62 (159.6 bb)
CO: $579.63 (579.6 bb)

Preflop: Hero is BB with K J
2 folds, CO raises to $2, 2 folds, Hero calls $1

Flop: ($4.50) 6 9 5 (2 players)
Hero checks, CO bets $4, Hero raises to $17.50, CO raises to $62.50, Hero calls $45

Turn: ($129.50) 9 (2 players)
Hero checks, CO checks

River: ($129.50) 2 (2 players)
Hero checks, CO bets $68.66, Hero calls $68.66

CO 21/16/8.6 after 95 hands
small postflop samples

I didnt want to put it in on the flop being so deep, cause I will only isolate myself against A:sX:s or 8:s7:s.
River? Bet/fold or x/call?