Cherished rendition of rare duets (9)
I believe the answer is:
treasured
'cherished' is the definition.
(synonyms)
'rendition of rare duets' is the wordplay.
'rendition of' is an anagram indicator (I've seen 'rendition' mean this).
'rare'+'duets'='rareduets'
'rareduets' with letters rearranged gives 'TREASURED'.
(Other definitions for treasured that I've seen before include "Valued" , "Valuable" , "Cherished, held dear" , "Loved" , "Chersihed, held dear" .)