Bloodsuckers; hangers-on (9)
I believe the answer is:
parasites
I believe this clue is a double definition.
'bloodsuckers' is the first definition.
(I've seen this in another clue)
'hangers-on' is the second definition.
(I've seen this in another clue)
(Other definitions for parasites that I've seen before include "Passengers" , "Hangers-on" , "unwelcome guests" , "They live off other organisms" , "they need indulgent hosts" .)