There's no definitive proof. He shouldn't be droped from Juventus either way, Juventus and FIFA arent law enforcement. If he's guilty and it can be proved 100% in court of law then they can deal with it. If it is not, then he should have the right to play soccer.
I think most clubs initially 'drop' the player so as not to distract from the rest of the team and to enable to player to get themselves sorted.
But out of curiosity, how do you think it should go? I remember a few years back, the same thing happened with an English player, Adam Johnson. He was briefly suspended after being accused of having a relationship with a 15 year old. He was later brought back into the team, and eventually sacked when he pleaded guilty to the charge. I believe he is still in prison.