Music maker’s nickname called out, with cheer echoing (9)
I believe the answer is:
harmonica
'music maker's' is the definition.
(harmonica is a kind of musical instrument)
'nickname called out with cheer echoing' is the wordplay.
'nickname' becomes 'monicker' (a monicker is a name or nickname).
'called out' indicates a 'sounds like' (homophone) clue.
'with' says to put letters next to each other.
'cheer' becomes 'rah' (rah is a triumphant cry).
'echoing' is a reversal indicator (echo can mean to reflect or bounce back).
'monicker' sounds like 'monica'.
'rah' reversed gives 'har'.
'monica' after 'har' is 'HARMONICA'.
(Other definitions for harmonica that I've seen before include "Mouth organ" , "musical instrument" , "Harp" , "Small wind instrument" , "An alternative mouth-organ" .)