Commercial delegation right to enter (9)
I believe the answer is:
admission
'right to enter' is the definition.
(I've seen this before)
'commercial delegation' is the wordplay.
'commercial' becomes 'ad' (abbreviation for advertisement).
'delegation' becomes 'mission' (synonyms).
'ad'+'mission'='ADMISSION'
(Other definitions for admission that I've seen before include "entry charge" , "acceptance" , "for which one may be charged" , "Right to go in" , "Ticket holders expect this" .)