"When is he leaving?"
Translation:Когда он уходит?
I'm a native speaker too. However I think that "Когда он уйдёт" is translated as "When is he going to leave?" or "When will he leave?"
"When is he leaving?" - is Present Continius. "Уйдёт" is unsuitable for this time.
There is definitely an implied future tense to this kind of present continuous construction with 'when' in English. The most common interpretation of 'When is he leaving?' would indeed be, 'When will he leave?', so it arguably corresponds better to уйдёт than уходит.
It is уедет. -Ехать-verbs have an irregular stem change in the non-past conjugation.
It should allow "уезжает." "Уедет" is perfective, and I think it changes the sense of the sentence to something like, "When will he leave" (same with "уидёт").
Yeah, technically you are right here. Sometimes I get annoyed with direct translations, especially when the meaning is pretty darn close to the same.
It doesn't like "Когда уходит"? I thought the "он" was optional if the verb is conjugated?
No, not in Russian. In the majority of cases the subject is mandatory, so it's safer to use it every time.