Always enter perhaps with a friend (9)
I believe the answer is:
eternally
'always' is the definition.
(eternally means always)
'enter perhaps with a friend' is the wordplay.
'perhaps' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'a friend' becomes 'ally' (an ally is a friend or supporter).
'enter' with letters rearranged gives 'etern'.
'etern'+'ally'='ETERNALLY'
(Other definitions for eternally that I've seen before include "Always and ever" , "all the time" , "Always and forever" , "For evermore" , "constantly" .)