Son is playing in Rhode Island for composer (7)
I believe the answer is:
rossini
'for composer' is the definition.
(Italian composer Gioachino Rossini)
'son is playing in rhode island' is the wordplay.
'playing' is an anagram indicator.
'in' indicates putting letters inside.
'rhode island' becomes 'RI' (US postal abbreviation).
'son'+'is'='sonis'
'sonis' is an anagram of 'ossin'.
'ossin' inserted into 'ri' is 'ROSSINI'.
(Other definitions for rossini that I've seen before include "Staff writer" , "whose barber was in Seville" , "Barber of Seville writer" , "Largo al factotum composer" , "Composer of 'The Barber of Seville' and 'William Tell'" .)