Was it ever proved that he did? There was some non-committal talk quoted, but nothing beyond that?
You also say "for example" - are there any other credible allegations that Assange "crossed the line"?
There is no proven accusation because Assange hasn't gone to trial, which is the part of the process where that standard applies.
The credible allegation part is the indictment handed down from a federal grand jury; this is the 'probable cause' standard.
What I meant was rather: has there been made any credible/sensible accusation for him being involved in hacking? Because while the drivel made it through the grand jury, it's still a vague answer without any allegations of follow-up. Could I help you crack a password hash? Sure, maybe I could. Am I now conspiring to hack into a military network? I rather think not. And that's even though you have my offer in writing.
No, which is why in the judgment every reference to a supposed attempt of "cracking a hash" is preceded by "alleged".