Society girl Italian poet takes in underground going north (9)
I believe the answer is:
debutante
'society girl' is the definition.
(I've seen this before)
'italian poet takes in underground going north' is the wordplay.
'italian poet' becomes 'dante' (I've seen this before).
'takes in' is an insertion indicator.
'underground' becomes 'tube' ('tube' can be a synonym of 'underground').
'going north' says the letters should be written backwards.
'tube' reversed gives 'ebut'.
'dante' going around 'ebut' is 'DEBUTANTE'.
(Other definitions for debutante that I've seen before include "Young lady making her first appearance in society" , "One entering society for the first time" , "Maiden speaker" , "girl coming out" , "one about to come out" .)