Worker with hair drives him round the junction (9)
I believe the answer is:
locksmith
'drives him round the junction' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'worker with hair' is the wordplay.
'worker' becomes 'smith' (smith is a kind of worker).
'with' is a charade indicator (letters next to each other).
'hair' becomes 'lock' (a lock of hair).
'smith' after 'lock' is 'LOCKSMITH'.
Can you help me to learn more?
(Other definitions for locksmith that I've seen before include "key figure" , "Maker of secure fasteners" , "Security expert" , "Yale scholar" , "laughing stock" .)