You pose a very loosely defined probability problem. The solver has to assume things to get a good answer for your question. I guess you mean a nine handed holdem game where all nine players play to the river for a showdown? I think that a series of combinations of monte carlo simulations and proability counting calulations could give some estimates to what you are looking for....Calculations have to me made at to what percentage of the time that both players have two SF cards in their hands. I don't think it is an easy problem to solve, and also not a realistic problem to solve. Poker casino managment determine size of the jackpot prize by keeping records on how often jackpots occur and the games that they occur in. Casino usually (very seldom) loose money on jackpots giveaways. Jackpots as you know are a form of advertizing to increase business....