Batter often aims for declaration (9)
I believe the answer is:
manifesto
'declaration' is the definition.
(I know that declaration can be written as manifesto)
'batter often aims' is the wordplay.
'batter' indicates an anagram (I've seen 'battered' mean this).
'often'+'aims'='oftenaims'
'oftenaims' is an anagram of 'MANIFESTO'.
'for' is the link.
(Other definitions for manifesto that I've seen before include "party programme" , "See 6" , "statement of policy" , "Written declaration of opinions" , "plans for a party" .)