Having alighted from the coach out of view of the audience (8)
I believe the answer is:
'having alighted' is the definition.
I can't tell whether this definition defines the answer.
'from the coach out of view of the audience' is the wordplay.
'from' becomes 'of' (of can mean from or belonging to).
'the coach' becomes 'stage' (stagecoach).
'out of' is an insertion indicator (some letters on the outside of others).
'view of the audience' becomes 'f' (I can't justify this - if you can you should believe this answer much more).
'ofstage' placed around 'f' is 'OFFSTAGE'.
Can you help me to learn more?
(Other definitions for offstage that I've seen before include "not visible from house" , "out of sight of the audience" , "Invisible to the audience" , "Not visible to the audience" , "behind the scenes" .)