Well, if it’s anything like the US, show up.
(At home – and, from what I can gather, most other places in the world – being called ‘Professor’ means you’ve really made it; a university department might only have one or two full Professors, whereas here just about any old schmuck put in charge of a classroom seems to get called ‘Professor,’ even adjuncts living below the poverty line – I’m not sure you even need a PhD)
Seriously, though, in the real world there’s no particular qualification you need to gain the title ‘Professor’ – it’s more like a job description than, say ‘Doctor’ (which implies a specific high-level academic or medical qualification). It probably means something like ‘senior/chief researcher’ and indicates that the person in question runs his or her own lab, or occupies an important government-appointed scientific position. Some of them may be appointed by the Pokémon League, depending on how much you think that organisation is in charge of.
Of course, it goes without saying that your surname has to be the name of a tree (although you can just get it legally changed for this purpose).
Pokémaniacal 