Noticing Dicky hosting ball under an assumed name (9)
I believe the answer is:
incognito
'under an assumed name' is the definition.
(I've seen this before)
'noticing dicky hosting ball' is the wordplay.
'dicky' indicates anagramming the letters (dicky can mean not functioning properly).
'hosting' means one lot of letters goes inside another (inserted letters are welcomed in or hosted).
'ball' becomes 'o' (O looks like a ball).
'noticing' anagrammed gives 'incgnito'.
'incgnito' enclosing 'o' is 'INCOGNITO'.
(Other definitions for incognito that I've seen before include "hiding identity" , "appear unidentifiable" , "In disguise" , "Keeping one's identity a secret" , "with unknown identity" .)