Sure about Republican fellow rising again (9)
I believe the answer is:
resurgent
'rising again' is the definition.
(I've seen this before)
'sure about republican fellow' is the wordplay.
'about' indicates an anagram.
'republican' becomes 'R' (political abbreviation).
'fellow' becomes 'gent' (synonyms).
'sure' is an anagram of 'resu'.
'resu'+'r'+'gent'='RESURGENT'
(Other definitions for resurgent that I've seen before include "Reviving after period of inactivity" , "given new life" , "Coming back to life" , "rising again" , "Reviving after a lull" .)