Not in English he isn't. Maybe it's an exception to what I assume is a rule, but it's jarring one. "He will/He'll be here soon."
I have Danish friends, and they use 'is' for future tense all the time and it's just like 'what do they teach you in school?!' But then again, in Britain we don't even have to learn a second language -- which I think is ridiculous.
Why not tidligt?
Because that would mean 'early' rather than 'soon'.