Extra playing soccer, say (9)
I believe the answer is:
accessory
'extra' is the definition.
(thesaurus)
'playing soccer say' is the wordplay.
'playing' indicates an anagram.
'soccer'+'say'='soccersay'
'soccersay' anagrammed gives 'ACCESSORY'.
(Other definitions for accessory that I've seen before include "Useful added item" , "Criminal's helper" , "Confederate" , "Supplementary item" , "Someone who helps another commit a crime" .)