Went to AC to watch the final table of the Borgata Summer Open ME yesterday. Called before hand and someone in the poker room told me the final table started at 3pm. Got there around 4pm and found out they played it yesterday. Real geniuses they got working there. My friend had never played a live tournament and wanted to so we played the 7pm $60+15 at the Showboat. 71 people. Top 10 were paid. I had very few hands early on, but during the 200/400 round I used my rock-like image to steal the blinds with [4s] in middle position. The very next hand I picked up [Qd] and took the blinds again. The hand after that I picked up AKo and raised slightly more. The big stack decided it was too much and fought back with a call. Flop came 234 and I pushed. He had to fold. After taking out a short stack with AK again vs AQ I had about 12,000+ in chips by the time the break came.
Now here is the pivotal hand of the tournament for me. Blinds are 300/600 not long after the break. I have K9o in the BB at a full 10 handed table. UTG+2 limps in (an older gentleman, sort of vanilla, not great, not bad, played his strong hands strong, his only perceptable weakness thus far was that he liked to go one card too far with mediocre hands sometimes) and it is folded around to me. I check.
Flop comes AT3 (suits never mattered in this hand so I'm not going to try to remember them). Turn comes another A. I bet 1200 into a 1500 pot and he thinks and calls. Pot is now 3900.
River is another T. Board reads AT3AT. I bet another 1200 and he thinks and pushes for 3600 total. Pot is now 8700 and it costs me 2400 to call. I still have about 7000+ if I lose. What do you do and why?