Brave and popular time traveller supported by papers (8)
I believe the answer is:
intrepid
'brave' is the definition.
('intrepid' can be a synonym of 'brave')
'popular time traveller supported by papers' is the wordplay.
'popular' becomes 'in'.
'time' becomes 't'.
'traveller' becomes 'rep' (travel company worker).
'supported by' says to put letters next to each other (letters go below - in down clue).
'papers' becomes 'id' (identification papers).
'in'+'t'+'rep'+'id'='INTREPID'
'and' is the link.
(Other definitions for intrepid that I've seen before include "Fearless, adventurous" , "stout" , "Novel" , "Fearlessly adventurous" , "Afraid not" .)