Local worker, margin squeezed in trade (9)
I believe the answer is:
bartender
'local worker' is the definition.
(I've seen this before)
'margin squeezed in trade' is the wordplay.
'margin' becomes 'end'.
'squeezed in' is an insertion indicator.
'trade' becomes 'barter' (synonyms).
'end' placed within 'barter' is 'BARTENDER'.
(Other definitions for bartender that I've seen before include "Liquor salesman" , "Server in pub" , "Someone serving drinks" , "Landlord perhaps" , "Pub employee" .)