One's sent to treat Cuban male in trouble (9)
I believe the answer is:
ambulance
'one's sent to treat' is the definition.
(vehicle sent to treat unwell people)
'cuban male in trouble' is the wordplay.
'in trouble' indicates anagramming the letters.
'cuban'+'male'='cubanmale'
'cubanmale' is an anagram of 'AMBULANCE'.
(Other definitions for ambulance that I've seen before include "one seen by accident" , "Vehicle designed to carry the sick" , "Emergency vehicle" , "It will bring you to hospital" , "Vehicle for transporting the sick" .)