Work with what’s given? I’m in favour of US tool (9)
I believe the answer is:
improvise
'work with what's given?' is the definition.
(as in to improvise with what's available)
'i'm in favour of us tool' is the wordplay.
'in favour of' becomes 'pro' (I've seen this before).
'us tool' becomes 'vise' (US spelling of 'vice').
'im'+'pro'+'vise'='IMPROVISE'
(Other definitions for improvise that I've seen before include "Talk without notes" , "Ad-lib" , "Quickly make changes" , "Perform spontaneously" , "Use whatever materials are to hand" .)