Robin Hood finally featured in best rare performance (9)
I believe the answer is:
redbreast
'robin' is the definition.
(synonyms)
'hood finally featured in best rare performance' is the wordplay.
'finally' says to take the final letters.
'featured in' indicates putting letters inside.
'performance' indicates anagramming the letters.
The final letter of 'hood' is 'd'.
'best'+'rare'='bestrare'
'bestrare' with letters rearranged gives 'rebreast'.
'd' inserted into 'rebreast' is 'REDBREAST'.
(Other definitions for redbreast that I've seen before include "One tweets" , "Bird" , "Type of robin" , "Flapper" .)