Colour that is raised on blue bedcover (9)
I believe the answer is:
eiderdown
'bedcover' is the definition.
(I've seen this before)
'colour that is raised on blue' is the wordplay.
'colour' becomes 'red' (red is a kind of colour).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'raised' says the letters should be written backwards (going up in a down clue).
'on' means one lot of letters go next to another.
'blue' becomes 'down' (both can mean sad).
'red'+'ie'='redie'
'redie' back-to-front is 'eider'.
'eider'+'down'='EIDERDOWN'
(Other definitions for eiderdown that I've seen before include "thermal insulation" , "Feather quilt" , "Find cover" , "I wondered about this warm bed covering" , "what may be on tonight" .)