Arrange one gate - it's wrong (9)
I believe the answer is:
negotiate
'arrange' is the definition.
(thesaurus)
'one gate it's wrong' is the wordplay.
'wrong' is an anagram indicator.
'one'+'gate'+'it'='onegateit'
'onegateit' is an anagram of 'NEGOTIATE'.
(Other definitions for negotiate that I've seen before include "I get a note (anag) - bargain" , "Deal, bargain" , "Pass round" , "as diplomat does" , "Bring about by mutual agreement" .)