I've read a couple of mock drafts and going in the 9th spot are Dan Williams, (Nose Tackle from Tennessee), Trent Williams (Offensive Tackle from Oklahoma), Brian Bulaga (Offensive Tackle from Iowa) and even Jimmy Clausen (QB from Notre Dame). I would take Bulaga and Clausen over Ben right now. The other two are okay prospects but I would rather take Ben over them (even with the 6 games).
Really depends on who you think will fall into that #9 spot, if you think it is Bulaga or Clausen that fall that far you do not trade the pick.
There is no way the Rams, Lions, Redskins (although who really knows), Chiefs, Seahawks, Browns (but you never know) or the Raiders taking a QB with their top picks (yes, I know that the Rams will take Bradford). So IF Clausen is there, you must grab him if you are the Bills.