Stand-in crew at first crazy about trip's start (8)
I believe the answer is:
stuntman
'stand-in' is the definition.
(I know that stuntman is a type of stand-in)
'crew at first crazy about trip's start' is the wordplay.
'crew' becomes 'man' (both can mean to staff or operate something).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'first crazy about trip's start' becomes 'stunt' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'man' put after 'stunt' is 'STUNTMAN'.
Can you help me to learn more?
(Other definitions for stuntman that I've seen before include "Double for a film's dangerous scenes" , "He acts riskily" , "one with special role in film" , "Movie extra who performs dangerous feats" , "Performer of dangerous acts in films etc" .)