Bookkeeper's sign -- managed to get hold of one (9)
I believe the answer is:
librarian
'bookkeeper's' is the definition.
(thesaurus)
'sign managed to get hold of one' is the wordplay.
'sign' becomes 'libra' (sign of the zodiac**).
'managed' becomes 'ran' (I've seen this before).
'to get hold of' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'ran' enclosing 'i' is 'rian'.
'libra'+'rian'='LIBRARIAN'
(Other definitions for librarian that I've seen before include "Philip Larkin was one at Hull University" , "Person in charge of books etc" , "Custodian of a collection of books" , "job!" , "Bookkeeper" .)