Perhaps overstuff overcoat, having eaten noodle soup (9)
I believe the answer is:
upholster
'perhaps overstuff' is the definition.
I can't tell whether this defines the answer.
'overcoat having eaten noodle soup' is the wordplay.
'overcoat' becomes 'ulster' (ulster is a kind of overcoat).
'having eaten' is an insertion indicator.
'noodle soup' becomes 'pho' (I can't explain this - if you can you should believe this answer much more).
'ulster' enclosing 'pho' is 'UPHOLSTER'.
Can you help me to learn more?
(Other definitions for upholster that I've seen before include "Provide furniture with padding, springs etc" , "Furnish seating" , "cover chair" , "Provide furnishings" , "something to do with furniture" .)