Little devil wandering around, making progress (9)
I believe the answer is:
improving
'making progress' is the definition.
'little devil wandering' is the wordplay.
'little devil' becomes 'imp' (I've seen this before).
'wandering' becomes 'roving' ('rove' can be a synonym of 'wander').
'imp'+'roving'='IMPROVING'
'around' is the link.
(Other definitions for improving that I've seen before include "Recovering" , "Getting better" , "Making better" .)