Fellow with vessel one cast provided (9)
I believe the answer is:
furnished
'provided' is the definition.
('furnish' can be a synonym of 'provide')
'fellow with vessel' is the wordplay.
'fellow' becomes 'fished' (I can't justify this - if you can you should believe this answer much more).
'with' means one lot of letters goes inside another.
'vessel' becomes 'urn' (urn is a type of container).
'fished' enclosing 'urn' is 'FURNISHED'.
'one cast' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for furnished that I've seen before include "Equipped with tables,chairs etc" , "Provided, supplied" .)