War captive sporting black eye? Victory could have been his? (9)
I believe the answer is:
shipowner
'victory could have been his?' is the definition.
(as in HMS Victory)
'war captive sporting black eye?' is the wordplay.
'war captive' becomes 'POW' (prisoner of war).
'sporting' means one lot of letters goes inside another (inserted letters wear or 'sport' others).
'black eye?' becomes 'shiner' ('shiner' can be a synonym of 'black eye').
'pow' placed inside 'shiner' is 'SHIPOWNER'.
(Other definitions for shipowner that I've seen before include "man over the line" , "Onassis, say" , "I've secured brig" , "Crafty proprietor" .)