If you are on the revenue side of things (i.e. want more $$s), then obviously you want 9 SEC games. If a team plays 9 SEC games, the negatives are as follows:
1) You get one less presumably easier game that would have allowed you to play 2nd and 3rd string players and rest some of the first string:
2) One more SEC game will lead to more injuries; this is particularly true since the top 12 teams will be in extra playoff games; Extra SEC games mean you must push your best players harder and longer to win conference games against an extra strong team.
3) Smaller schools will be effected because it is one less big revenue game that they won't get: 4) The elite schools with the deeper bench will be the ones who will benefit. Their 2nd and 3rd teams are as good as many team's first teams so they can play the extra tough game with lesser problems. The rich reap the benefits of the rule change.
As players get more and more bulked up and faster, something is going to give and likely it will be more serious injuries. I think we are seeing it now. You can only squeeze so much out of 18 to 21 year olds before injuries mount up. I say stick with the 8 SEC games and slow down the insanity.