He moves a lot in his chair - not quite fidget but toned down restlessness (J types are in my experience very static)
The focus of his attention is split (he is oober consious of the crowed behind him - this may of course be an act - it's the way it's done... J types I'd say focus in one direction, and then the other, p types split their field of vision if you like).
The sense of humour - dropping witticisim to the audience
Charm in a bashful unasumming way (J types in my experience - WAY more direct)
He commented of having too many words in his earlier lyrics thats not J liked
His innovation in order to write lyrics
Entreapenure - although to be honest the guys in the suits tend to do that for the artists so may be irrelevant..
I guess both J's and P's are focused on their thing to an obsessional level.
Just an oppinion, based on what I saw in the interview... mainly the movement, the bashfulness and split attention it has to be said.... So I'm sure you guys who have seen this person multiple times have a better handle on type...