It really varies since its all about club head speed not really your level of golfer.
As a kid I would hit it 160-170. As an old out of shape player 140-150.
big difference these days is the clubs have been delofted so they all go about 10-15 yds further than the clubs of 20-30 yrs ago. So a 9 iron now is really an 8 iron of the clubs from 2000 and before, so it goes further.
But 110-140 would probably be the norm of a 9 iron depending on how hard you swing. For most people it would be better to swing a little easier and a little shorter and control it better.
