Schedule inverted by a sod of a troublemaker (8)
I believe the answer is:
agitator
'a troublemaker' is the definition.
(agitator is a kind of troublemaker)
'schedule inverted by a sod' is the wordplay.
'schedule' becomes 'rota' (I've seen this before).
'inverted' says the letters should be written backwards.
'by' means one lot of letters go next to another.
'sod' becomes 'git' (both can mean an annoying person).
'rota' backwards is 'ator'.
'a'+'git'='agit'
'ator' after 'agit' is 'AGITATOR'.
'of' is the link.
(Other definitions for agitator that I've seen before include "One stirring up (things)" , "Got tiara for a trouble-maker" , "One fomenting trouble" , "washing machine" , "One stirring up trouble" .)