In RADA, get trained to become an actor (9)
I believe the answer is:
tragedian
'an actor' is the definition.
(tragedian is a kind of actor)
'in rada get trained' is the wordplay.
'trained' indicates an anagram (to train can mean to grow something into a shape).
'in'+'rada'+'get'='inradaget'
'inradaget' anagrammed gives 'TRAGEDIAN'.
'to become' is the link.
(Other definitions for tragedian that I've seen before include "Egad, I rant about dramatic actor" , "Egad, I rant about actor in sad drama" , "Serious actor" , "actor in Macbeth?" , "A great din (anag) - actor" .)