After turning pro, he wins title (9)
I believe the answer is:
ownership
'title' is the definition.
(legal term for ownership)
'after turning pro he wins' is the wordplay.
'pro he wins' can be anagrammed to 'OWNERSHIP'.
But, I'm not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for ownership that I've seen before include "The right of possessing something" , "Legal title" , "Proprietorship, possession" , "Proprietary right of possession" .)