I believe you have to suspend Davis, just to send the sign that players have to stay out of the stands.
8 games is ridiculous. He did nothing abusive to any fan.
I suspend Davis 1 game for going into the stands, assuming that's all he did - same as the suspension for leaving the bench during a fight, and that's how I sell it if I'm the commissioner. If he used profanity or threatened the fan, make it 5 games. If he touched the fan in any manner, make it 15 games. And if he committed any violent act against the fan, make it 25 games.