One responsible for arranging rare song, I suspect (9)
I believe the answer is:
organiser
'one responsible for arranging' is the definition.
'rare song i suspect' is the wordplay.
'suspect' is an anagram indicator.
'rare'+'song'+'i'='raresongi'
'raresongi' anagrammed gives 'ORGANISER'.
(Other definitions for organiser that I've seen before include "storage container" , "One managing" , "One making arrangements" , "Rosie rang the person in charge of the arrangements" , "Runner" .)