There's just one story of him being drunk and disorderly, which was over six years ago while the season was over. As for being seen with beer, I don't think that it's too much of a big deal for a player to have a drink now and then.
The only story that has shown beer affecting his performance is the one in 2009, but the alcohol presumably didn't have an effect on him for that long in the season as he found he net in the first and second games of the season.
It's knee-jerk to say Rooney won't be at United next season.