Trouble means taking in youth with a scooter (9)
I believe the answer is:
incommode
'trouble' is the definition.
(synonyms)
'means taking in youth with a scooter' is the wordplay.
'means' becomes 'income' (someone's financial means).
'taking in' means one lot of letters goes inside another.
'youth with a scooter' becomes 'mod' (the mod subculture is famous for using scooters).
'income' going around 'mod' is 'INCOMMODE'.
(Other definitions for incommode that I've seen before include "Hassle" , "Trouble" , "inconvenience" , "Put out" , "Bother" .)