Host and reporters endlessly go in (9)
I believe the answer is:
presenter
'host' is the definition.
(e.g. for a television show)
'reporters endlessly go in' is the wordplay.
'reporters' becomes 'press' (members of the press).
'endlessly' means to remove the last letter.
'go in' becomes 'enter' (as in entering a building).
'press' with its final letter taken off is 'pres'.
'pres'+'enter'='PRESENTER'
'and' acts as a link.
(Other definitions for presenter that I've seen before include "TV/radio introducer" , "anchor?" , "Radio/TV personality" , "TV person" , "Compere" .)