(Projoy) There are some nouns that really ought not to be er, verbed. I'd say début is one of them. I'd have phrased it differently or said first started. (Darren) I like "debutted". It sounds like an American whose arse has fallen off.
[Darren] No, but I guess some other people use "debutted" in all seriousness. I guess it's because the 't' is silent, so it feels it needs a second, voiced 't' to enable the "ed" ending to click on. Same problem, of course, with past-tensing any noun or verb that ends on a vowel sound, such as "diminuendo'd" (but for some reason not "précised")
I think debuted is singularly infelicitous, mostly because of the pronunciation issue – is it debutted, daybood, debood, daybutted? Made his début’ seems the best way out to me.