Ceremony with a grim style adopted by The King? (9)
I believe the answer is:
pompadour
'style adopted by the king?' is the definition.
(hairstyle worn by Elvis Presley, 'The King')
'ceremony with a grim' is the wordplay.
'ceremony' becomes 'pomp' (I've seen this in another clue).
'with' is a charade indicator (letters next to each other).
'grim' becomes 'dour' (synonyms).
'pomp'+'a'+'dour'='POMPADOUR'
(Other definitions for pompadour that I've seen before include "Hairstyle associated with a mistress of Louis XV" , "Lady" , "Extravagant quiff" , "twenty down [HAIRDO]" , "18th century hairstyle employing a pad at the front to add bulk" .)