Go to "Rosters", then choose "Edit Player". Select the players that you want to be rated 99. Go to his attributes, then increase everything.
Earning campus challenge credits and running up your score/stats
Create your own juggernaut school/team. Edit the roster so your team is filled with studs. Enter season mode with your team and under the preseason options, schedule as many 1-AA teams as possible. Set your playing time for 15 minutes and enjoy the ride. If you have the unlimited time-out cheat, you can use it here and stop the clock after any play finishes in-bounds. This will give you more time to compile stats. Note: Doing this may increase your game time to over 90 minutes (and possibly 120) of "real-time". If you are going to use the time-out cheat, take a 15-minute break when you hit the half time point of your game. Also, note that campus challenge points are awarded based on your level of play. Heisman is the hardest level, but you also get increased value on your campus challenge credits.
Announce names instead of numbers
If you would like to hear the announcers call out your teams names rather than their numbers, all you have to do is put their roster in. Go to the options screen, go to "Edit Rosters" and insert the names under "Player Info". After you insert them, play a game and your team's names will be announced.