Bursar more confident after rate adjusted (9)
I believe the answer is:
treasurer
'bursar' is the definition.
(thesaurus)
'more confident after rate adjusted' is the wordplay.
'more confident' becomes 'surer' ('sure' can be similar in meaning to 'confident').
'after' is a charade indicator (letters next to each other).
'adjusted' indicates an anagram.
'rate' is an anagram of 'trea'.
'surer' put after 'trea' is 'TREASURER'.
(Other definitions for treasurer that I've seen before include "Financial controller" , "Bursar" , "Fund manager" , "he's got the money" , "Officer in charge of the money" .)