Charlie leaves a group chat crudely making sign (9)
I believe the answer is:
autograph
'sign' is the definition.
(autographing is a kind of signing)
'charlie leaves a group chat crudely' is the wordplay.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'leaves' suggests deleting specific letters.
'crudely' indicates anagramming the letters.
'a'+'group'+'chat'='agroupchat'
'agroupchat' with 'c' taken out is 'agrouphat'.
'agrouphat' with letters rearranged gives 'AUTOGRAPH'.
'making' is the link.
(Other definitions for autograph that I've seen before include "Sign" , "Signer will give this" , "(Celebrity's) signature" , "One's signature" , "a collector's item perhaps" .)