Small marsupial’s time to settle for the night (5)
I believe the answer is:
roost
'settle for the night' is the definition.
(as in a bird roosting)
'small marsupial's time' is the wordplay.
'small marsupial's' becomes 'roos' (short for kangaroo; 'small' indicates an abbreviation).
'time' becomes 't' (abbreviation).
'roos'+'t'='ROOST'
'to' acts as a link.
(Other definitions for roost that I've seen before include "Temporary place to stay" , "Fowl's perch" , "Thin paper" , "Bats' settling place" , "Perch where bird sleeps" .)