Court instrument always finding criminal (9)
I believe the answer is:
racketeer
'criminal' is the definition.
(I know that racketeer is a type of criminal)
'court instrument always' is the wordplay.
'court instrument' becomes 'racket' (tennis racket - used on a tennis court).
'always' becomes 'eer' (poetic way of saying ever).
'racket'+'eer'='RACKETEER'
'finding' acts as a link.
(Other definitions for racketeer that I've seen before include "Dodgy dealer" , "Fraudulent businessman" , "Criminal trader" , "someone to make a dodgy deal?" , "someone on the fiddle" .)