Itinerant composer appearing in Albert Hall performance, popular at last (9)
I believe the answer is:
traveller
'itinerant' is the definition.
(I've seen this before)
'composer appearing in albert hall performance popular at last' is the wordplay.
'composer' becomes 'ravel' (Maurice Ravel).
'appearing in' indicates putting letters inside.
'at last' suggests the final letters.
The final letters of 'albert hall performance popular' are 'tler'.
'ravel' going inside 'tler' is 'TRAVELLER'.
(Other definitions for traveller that I've seen before include "One on a trip" , "becoming less narrow-minded over time?" , "'I met a . . . . . . . . . from an antique land' (P.B.Shelley)" , "Itinerant" , "fare?" .)