I'm of two minds...
on the one hand being late on the first day is crazy unprofessional and
could be a huge red flag
On the other hand ish happens, and sometimes insanely talented and creative people aren't the best at keeping on the clock but prove their worth in the hours/efforts they do invest. But yeah...sometimes ish just happens.
I don't see being late once as a character issue necessarily, it could be but why cut off something that could be a good thing for both parties involved (assuming there's an upside if the person was hired in the first place)?
I think everyone deserves one chance, costs nothing to grant one and if anything provides notice to pay closer attention, and then axe if issues of (un)professionalism persist.
I would def speak to the person though, and let them know that ish is unacceptable. Reason would matter here, not for the content of the reply but more to see how the person handles it. That is always key
Are they genuinely embarrassed and do they arrive early every day for the next week? if so you know they know they fucked up and are trying to redeem your assessment of them
tl;dr, would def not fire. would speak to and not let the issue persist, but humans are fallible and we miss out on a lot if we cut peeps out too quickly.