He sees details on rubbish gold (9)
I believe the answer is:
spectator
'he' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'details on rubbish gold' is the wordplay.
'details on' becomes 'spec' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rubbish' becomes 'tat' (low-quality items or material).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'spec'+'tat'+'or'='SPECTATOR'
'sees' acts as a link.
Can you help me to learn more?
(Other definitions for spectator that I've seen before include "member of the crowd" , "weekly publication" , "Onlooker at game" , "observer" , "Cat poster (anag.)" .)