Sign top player at last — current seed (9)
I believe the answer is:
capricorn
'sign' is the definition.
(a sign of the zodiac)
'top player at last current seed' is the wordplay.
'top' becomes 'cap' (cap is a kind of top).
'player at last' becomes 'r' (I am not sure about this - if you are sure you should believe this answer much more).
'current' becomes 'I' (symbol for electric current).
'seed' becomes 'corn' (corn is a kind of seed).
'cap'+'r'+'i'+'corn'='CAPRICORN'
(Other definitions for capricorn that I've seen before include "Sign of winter" , "Goat star sign" , "Constellation known as The Goat" , "Tropic - Zodiac sign" , "7 [SIGN OF THE ZODIAC]" .)