Agent recalled bygone artiste (9)
I believe the answer is:
performer
'artiste' is the definition.
(I've seen this before)
'agent recalled bygone' is the wordplay.
'agent' becomes 'rep' (short for representative).
'recalled' says the letters should be written in reverse.
'bygone' becomes 'former' (I can't explain this - if you can you should believe this answer much more).
'rep' in reverse letter order is 'per'.
'per'+'former'='PERFORMER'
Can you help me to learn more?
(Other definitions for performer that I've seen before include "Thespian" , "Fred Astaire, say" , "Such as a musician or actor" , "artist" , "Eg 9 [ACTRESS]" .)