Next in line for gold on back of victory (9)
I believe the answer is:
successor
'next in line' is the definition.
(thesaurus)
'gold on back of victory' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'on' is a charade indicator (letters next to each other).
'back of victory' becomes 'success' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'or' put after 'success' is 'SUCCESSOR'.
'for' is the link.
Can you help me to learn more?
(Other definitions for successor that I've seen before include "One who follows another" , "One taking over from another" , "Person who follows next in order" , "for one of the following people" , "Follower (in post)" .)