Former cat lover initially objects and cries out (8)
I believe the answer is:
exclaims
'cries out' is the definition.
('exclaim' can be a synonym of 'cry out')
'former cat lover initially objects' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'initially' suggests taking the first letters.
'objects' becomes 'aims' ('aim' can be a synonym of 'object').
The first letters of 'cat lover' is 'cl'.
'ex'+'cl'+'aims'='EXCLAIMS'
'and' acts as a link.
(Other definitions for exclaims that I've seen before include "Cries out from pain or surprise" , "Suddenly cries out" , "Cries out in climaxes" .)