Bookkeeper but not necessarily an accountant (9)
I believe the answer is:
librarian
This clue might be a double definition.
'bookkeeper' is the first definition.
(librarians look after books)
'accountant' is the second definition.
(thesaurus)
'but not necessarily an' is the link.
I am not very happy about this link. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for librarian that I've seen before include "Custodian of a collection of books" , "Bookish type" , "Philip Larkin was one at Hull University" , "job!" , "One dealing with books" .)