9ac. Youngssster (9) Ans - Stripling
12ac. Non-U poet's extremely angry, apparently (2,4,3) Ans - So they say.
8d. A painter is very dry outside (6)
ans - Tissot
and if anyone solved 4ac (the clue is too complicated, with references to 3 other clues, to try to explain if you don't have the paper) I'd be interested to see how that derives.