Priest gets beer for composition (9)
I believe the answer is:
pastorale
'for composition' is the definition.
(pastorale is a kind of musical composition)
'priest gets beer' is the wordplay.
'priest' becomes 'pastor' (pastor is a type of priest or minister).
'gets' means one lot of letters go next to another.
'beer' becomes 'ale' (type of beer).
'pastor'+'ale'='PASTORALE'
(Other definitions for pastorale that I've seen before include "Some country music" , "Composition about rural life" , "What may feature actors" , "play about 2 [ARCADIA]?" , "Musical work" .)