Club member managed to keep one on schedule (8)
I believe the answer is:
rotarian
'club member' is the definition.
(member of a Rotary Club)
'managed to keep one on schedule' is the wordplay.
'managed' becomes 'ran' (both can mean organised or was in charge of).
'to keep' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'on' is a charade indicator (letters next to each other).
'schedule' becomes 'rota' (a rota is a schedule).
'ran' placed around 'i' is 'rian'.
'rian' after 'rota' is 'ROTARIAN'.
(Other definitions for rotarian that I've seen before include "Member of a society of businessmen promoting community service" , "Charitable businessman" , "Member of club doing community service" , "Charitable society member" .)