Key to take note as soon as daughter's settled snugly (9)
I believe the answer is:
ensconced
'settled snugly' is the definition.
(I've seen this in another clue)
'key to take note as soon as daughter's' is the wordplay.
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'to take' indicates putting letters inside (inserted letters are taken in).
'note' becomes 'n' (abbreviation).
'as soon as' becomes 'once' (once can mean immediately after).
'daughter' becomes 'd' (genealogical abbreviation).
'esc' going around 'n' is 'ensc'.
'ensc'+'once'+'d'='ENSCONCED'
(Other definitions for ensconced that I've seen before include "Safely established" , "in safe seat" , "Settled comfortably" , "Installed" .)