I'm gonna say he had A9 or A10 thinking Ace 9 by the way you described how he played. The ace 8 call with a thirsd of his stack is what leads me to believe he likes plaing raggy ace cards and unless he is really dumb he isn't leading out into you knowing you could have an over pair. you still had plenty behind to play the short stack I don't think it is worth risking your tournament life with. The only draw he could have had is like jq and that is near impossible since you have qq just my thinking