I'd go a little higher on the KC game, a win there I think locks the tiebreak over PIT and KC and then 9-7 becomes likely to get them in. A loss, then you're realistically assuming KC finishes ahead of you with their easy finishing schedule, and it just gets a lot tougher.
They could actually lose a tiebreaker to Pittsburgh if they win all 3 non-conference games and Pittsburgh loses to Seattle. 9-7 with an assumed loss to the Jets is a very dangerous place to be. If we beat the Chiefs but lose to the Jets the tiebreaker with the Jets inside the division could flip (if the Jets beat the Dolphins this week it would go to strength of victory, which is fluid). In that case, the win over the Chiefs doesn't mean squat, because the Chiefs would likely win tiebreakers with the Jets (their conference record is very good). A three way tie with the Texans and Chiefs would also probably not do us any good if we lose to the Texans.
Beat KC and the Jets, and yes, more likely than not you only need 9 wins (that potential KC-HOU-BUF three way tie is still scary though). If Miami beats the Jets this week (thus clinching a tiebreaker for us with the Jets even if we lose to them...well, unless they somehow beat New England), then yes, we'll probably only need 9 wins if we beat KC. The only way I think 9-7 is safe as of right now though is if those wins include KC and the Jets. KC/HOU/2 NFC teams gives us a pretty good shot, for sure (as indicated by summing 35), but if you told me that's what we were going to do right now, I'd have to assume we blew a play-in game against the Jets.
EDIT: Incidentally,
losing to Kansas City actually clinches the tiebreaker against the Jets (unless they somehow beat New England), adding to the reason they should actually be rooting for the Bills this week. KC and Pittsburgh could shut them out of the playoffs even if they play well down the stretch, especially if you assume the Jets will lose to New England. But they have a chance to hand the Bills a loss themselves. And even if they still end up losing the intradivisional tiebreak to Buffalo, it behooves them for Buffalo to win the inter-division tiebreak as soon as possible so they can jump into the fray.
E2: Also worth noting is that if you go to ESPN's playoff machine and decide games by power rankings (that is, the better team according to ESPN's "experts" wins every game, the Bills actually lose to KC then run the table, taking the 6th seed at 10-6. Pittsburgh has a rough schedule going out. They could easily be in the mix at 9-7, and a NYJ/HOU/2 NFC teams package of wins has the Bills sitting pretty in the tiebreakers there. None of this approaches where we're "safe", but there are certainly paths to the playoffs if we lose to KC.
VS.
