Sibling success after Latin edict rubbished (9,4)
I believe the answer is:
identical twin
'sibling' is the definition.
(identical twin is a kind of sibling)
'success after latin edict rubbished' is the wordplay.
'success' becomes 'win'.
'after' is a charade indicator (letters next to each other).
'rubbished' is an anagram indicator.
'latin'+'edict'='latinedict'
'latinedict' is an anagram of 'identicalt'.
'win' after 'identicalt' is 'IDENTICAL TWIN'.
(Other definitions for identical twin that I've seen before include "One of two from the same fertilised egg" , "Lookalike sibling" .)