No. The mj and paraphenalia was found in the car and claimed by the girl. She was charged with possession in addition to attempted armed robbery. SHE still has an uphill climb due to that, but since none was found on Jackson, he was not charged with possession. Legally, he is in the clear unless some entirely new evidence comes up, which seems unlikely at this point.
Now, his legal situation is only part of the story. If a guy is prosecuted and/or convicted of a serious crime by the legal system, the coaches wouldn't have much choice about keeping them, as a practical matter. But that doesn't mean that players can't be diciplined (including dismissal) for things that aren't illegal. The first time we hear about a player calling Coach O a dumbA$$, you'd have a chance to see the difference. That's not illegal, but the fact that the player may not have commited a crime won't save him. Likewise, it's not illegal to show your rear-end, like Brandon Warren....
With all of that said, it appears from the police investigation that JJ likely did not know before nor immediately after what those two knuckleheads did and he appears to have fully cooperated with the police. He didn't violate curfew, either. I think a two game suspension is plenty for having associated with Nu'Keese and Mike Edwards, because it appears that's about all he did. Shoot, Kiffin recruited them and he isn't getting fired for this, since there was no way to predict that they would do this. You can't reasonably hold a person accountable for someone else's actions - if you could I guess we'd have to disband the team and close the University.
Let him play. And let him know that this is his last chance.