Declare gold to be academic (9)
I believe the answer is:
professor
'be academic' is the definition.
(I've seen this before)
'declare gold' is the wordplay.
'declare' becomes 'profess' (professing is a kind of declaring).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'profess'+'or'='PROFESSOR'
'to' is the link.
(Other definitions for professor that I've seen before include "Member of an academic faculty" , "Leading academic" , "Head of faculty, department" , "chairman?" , "Fellow" .)