Message admitting king made up place of worship (5-4)
I believe the answer is:
notre-dame
'place of worship' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'message admitting king made up' is the subsidiary indication.
'message' becomes 'note' (note is a kind of message**).
'admitting' is an insertion indicator.
'king' becomes 'r' (r is abbreviation for rex).
'up' is a reversal indicator (in down clue: letters go upwards).
'made' in reverse letter order is 'edam'.
'r'+'edam'='redam'
'note' enclosing 'redam' is 'notredame'.
Can you help me to learn more?
(Other definitions for notre-dame that I've seen before include "tourist spot" , "Parisian building" .)