Woodworker has to nag to get in (9)
I believe the answer is:
carpenter
'woodworker' is the definition.
(carpenter is a kind of woodworker)
'nag to get in' is the wordplay.
'nag' becomes 'carp' (I've seen this in another clue).
'to get in' becomes 'enter' ('enter' can be a synonym of 'get in').
'carp'+'enter'='CARPENTER'
'has to' acts as a link.
(Other definitions for carpenter that I've seen before include "Wood worker" , "Find fault with record" , "Karen was one" , "job" , "Chippy" .)