He conducted opera back in Northern Ireland (9)
I believe the answer is:
toscanini
'he conducted' is the definition.
(I've seen this before)
'opera back in northern ireland' is the wordplay.
'opera' becomes 'tosca' (Giacomo Puccini opera).
'back' is a reversal indicator.
'northern ireland' becomes 'NI' (abbreviation).
'in' reversed gives 'ni'.
'tosca'+'ni'+'ni'='TOSCANINI'
(Other definitions for toscanini that I've seen before include "Old conductor" , "Maestro" , "Music director" , "He conducted" , "Virtuoso conductor" .)