Musical yours truly left? Repulsive! (9)
I believe the answer is:
melodious
'musical' is the definition.
('melodious' can be a synonym of 'musical')
'yours truly left? repulsive' is the wordplay.
'yours truly' becomes 'me'.
'left?' becomes 'l' (common abbreviation).
'repulsive' becomes 'odious' (I've seen this before).
'me'+'l'+'odious'='MELODIOUS'
(Other definitions for melodious that I've seen before include "music to the ears!" , "Tuneful" , "Sweet'" .)