Kid at home playing opera (3,6)
I believe the answer is:
the mikado
'opera' is the definition.
(I've seen this before)
'kid at home playing' is the wordplay.
'playing' indicates an anagram.
'kid'+'at'+'home'='kidathome'
'kidathome' anagrammed gives 'THE MIKADO'.
(Other definitions for the mikado that I've seen before include "Gilbert and Sullivan operetta" , "musical entertainment" , "comic opera" , "Staged work" , "Gilbert & Sullivan's Japanese operetta" .)