Christian, perhaps silent about popular English leader of rebellion (8)
I believe the answer is:
mutineer
'christian perhaps' is the definition.
(Fletcher Christian, mutineer on the HMS Bounty)
'silent about popular english leader of rebellion' is the wordplay.
'silent' becomes 'mute' (synonyms).
'about' is an insertion indicator.
'popular' becomes 'in' ('in' can mean trendy).
'english' becomes 'E' (abbreviation as in OED).
'leader of' suggests taking the first letters.
The initial letter of 'rebellion' is 'r'.
'mute' enclosing 'in' is 'mutine'.
'mutine'+'e'+'r'='MUTINEER'
(Other definitions for mutineer that I've seen before include "Openly rebellious person" , "Rebellious soldier" , "Seafarer or soldier who refuses to obey authorities" , "Participant in rebellion" , "Seditionist" .)