mopkins
King Kong
Big swings like that out of Vegas are and indication that they either have no clue how the game will go, or that they've got lopsided bets placed and they're trying to steer the money. Almost always a combination of both because one is a function of the other. There had to be a shitload of people taking that -9. On the surface that looks like a dumb mistake, but it obviously got a bunch of attention (enough to shave 4.5) which is what they want.
As far as Vegas is concerned this will end up being a pick'em with (like @MelroseHawkins said) a small home field edge. They looooooove these games because there are way more suckers who think they're sharks than actual sharks, and these games bring suckers out of the woodwork.
I believe that -9 opening was just an offshore aberration. Usually there's one or two offshore sites that try to set an early line to get the early action. If you look at the vegas opening line it was set at -5 which is about where it is now.
http://www.vegasinsider.com/college-football/odds/las-vegas/