Australian native came upon the vacant compartment (8)
I believe the answer is:
roomette
'compartment' is the definition.
(I know that roomette is a type of compartment)
'australian native came upon the vacant' is the wordplay.
'australian native' becomes 'roo' (informal term for kangaroo).
'came upon' becomes 'met' (I've seen this in another clue).
'vacant' says to hollow out the word (remove centre letters) (a vacant or emptied out form of the word).
'the' with its middle removed is 'te'.
'roo'+'met'+'te'='ROOMETTE'
(Other definitions for roomette that I've seen before include "Small bed space to let - or to meet (anag)" , "Manhattan bedsit?" , "Small sleeping accommodation to let" , "cramped accommodation?" .)