How to play K-K for maximum value.

PokerStars Game #1678562988: Hold'em No Limit ($0.50/$1.00) - 2005/05/11 - 16:06:10 (ET)
Table 'Ilona' Seat #4 is the button
Seat 1: whozitt ($23.85 in chips)
Seat 2: jg23 ($45.25 in chips)
Seat 3: pincharrata ($171.65 in chips)
Seat 4: lobo54 ($92.90 in chips)
Seat 5: MalYZ ($64.95 in chips)
Seat 6: Briv0086 ($151.70 in chips)
Seat 7: wolfpack31 ($34 in chips)
Seat 9: dsaxton ($137.05 in chips)
MalYZ: posts small blind $0.50
Briv0086: posts big blind $1
spider44: sits out
*** HOLE CARDS ***
Dealt to dsaxton [3c 3h]
wolfpack31: calls $1
dsaxton: calls $1
whozitt: folds
jg23: folds
pincharrata: raises $3 to $4
lobo54: folds
MalYZ: calls $3.50
Briv0086: folds
wolfpack31: folds
dsaxton: calls $3
*** FLOP *** [9s 5c 6h]
MalYZ: checks
dsaxton: checks
pincharrata: bets $3
MalYZ: calls $3
dsaxton: folds
*** TURN *** [9s 5c 6h] [6s]
MalYZ: checks
pincharrata: bets $2
MalYZ: raises $3 to $5
pincharrata: calls $3
*** RIVER *** [9s 5c 6h 6s] [Qd]
MalYZ: bets $10
pincharrata: raises $149.65 to $159.65 and is all-in
MalYZ: calls $42.95 and is all-in
*** SHOW DOWN ***
pincharrata: shows [6d 6c] (four of a kind, Sixes)
MalYZ: mucks hand
pincharrata collected $132.90 from pot
*** SUMMARY ***
Total pot $135.90 | Rake $3
Board [9s 5c 6h 6s Qd]
Seat 1: whozitt folded before Flop (didn't bet)
Seat 2: jg23 folded before Flop (didn't bet)
Seat 3: pincharrata showed [6d 6c] and won ($132.90) with four of a kind, Sixes
Seat 4: lobo54 (button) folded before Flop (didn't bet)
Seat 5: MalYZ (small blind) mucked [Kh Kc]
Seat 6: Briv0086 (big blind) folded before Flop
Seat 7: wolfpack31 folded before Flop
Seat 9: dsaxton folded on the Flop