It's ok to boo the coaches (ahem...Kevin Cosgrove).
The only problem with that statement is that fans can't direct boos towards any specific person during the game (they could if individuals are being introduced before the game or during half-time, ala "here's your Athletic Director, Steve Pederson". Fans: "BOOOOOOO!!!!"), so when you boo during the game, it's felt by the coaches, players and everyone involved with the team. If you're booing at the defense, believe it or not, the players feel it too, not just the coach.
On the other subject, OU was never going undefeated with a freshman QB. I'd rather they lose early and get a shot back at the title game as the rest of the field loses later. This year more than any in recent memory looks like a toss-up on who'll be playing in the B(C)S game. Nobody looks good enough to go undefeated. USC has too many road games that count. LSU has too many tough games, period. Don't even get me started on the joke that is the Big Ten. Sad thing is, the Big 12 isn't much better.