Campaign worker (9)
(Other definitions for canvasser that I've seen before include "Electioneer" , "collector of views" , "Political assistant" , "employed during an election" , "One soliciting votes" .)
'campaign worker' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for aide that I've seen before include "Personal assistant in the military" , "Leader's assistant" , "Confidential assistant or advisor" , "Officer in attendance" , "Second" .)