Striking scaffolder provides balance for canoe (9)
I believe the answer is:
outrigger
'for canoe' is the definition.
(outrigger canoe is a kind of canoe)
'striking scaffolder' is the wordplay.
'striking' becomes 'out' (striking out is a common phrase).
'scaffolder' becomes 'rigger' (I've seen this before).
'out'+'rigger'='OUTRIGGER'
'provides balance' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for outrigger that I've seen before include "Canoe with stabilisers" , "projection for various purposes" , "Type of boat with external supports" , "Git, our Reg (anag.); boat" , "Beam" .)