Wide boy always holding up item of tennis gear (9)
I believe the answer is:
racketeer
'wide boy' is the definition.
(I've seen this before)
'always holding up item of tennis gear' is the wordplay.
'always' becomes 'eer' (poetic way of saying ever).
'holding up' says to put letters next to each other (some letters go underneath or hold up others).
'item of tennis gear' becomes 'racket' (tennis racket).
'eer' after 'racket' is 'RACKETEER'.
(Other definitions for racketeer that I've seen before include "Criminal trader" , "tennis player?" , "Capone, for one" , "someone to make a dodgy deal?" , "fraudster" .)