> which had the exact name of an iOS developer on Fiverr.com - the name is not generic, and is long, so it can't really be a coincidence.

You could confront the student and say that they didnt submit their exam; that this other name came up instead. Have them explain if that's their name and work.

Realistically, they only cheat themselves. Best to scare the crap out of them and report they likely cheated but no punishment.