Personally, it really depends on where in the tournament you are. I am assuming this was heads up, but were you two the last two players? If not, I would not have played your hand from the start. So, for this, I will assume you two were the last players. In that case, I probably would have raised him to at least 3,000. By just calling, you pretty much "tell" him you are chasing soemthing, which you are. After the flop, you have 20 outs. (The nine other club cards available, plus four aces and four nines; also, it can be safe to assume your opponent may have just made top pair and your king becomes an out as well, giving you three additional outs). Before the turn, each out is worth four percentage points towards your odds of winning. This gives you a 80% chance of winning. After the turn card, your odds are sliced in half if you don't get a club, ace or nine. That gives you a 40% chance of catching your winning hand. However, now that the board has paired you have to be extra careful that your opponent hasn't hit a full house or a set. The full boat takes away all of your outs and the set takes away three of your outs. Best case scenario is your odds are reduced to 32%, but worse case scenario is you are drawing dead and have a 0% chance. This seems to be where you made your error. When your opponent went all in at that time, you had less than half the chance you did the round before. Therefore, you should have folded. Or, had raised him before that, which I already suggested. As for whether or not you should go all in with only the nuts, it really depends. You should be the aggressor throughout, but there is never really a need to risk all your chips unless you know for sure you have the best hand at that given time, and even then, by looking at the board, you can hypothesize what their odds may be.