Too keen to agree exchange after some deliveries (9)
I believe the answer is:
overeager
'too keen' is the definition.
(I've seen this before)
'agree exchange after some deliveries' is the wordplay.
'exchange' indicates an anagram.
'after' means one lot of letters go next to another.
'some deliveries' becomes 'over' (I've seen this before).
'agree' with letters rearranged gives 'eager'.
'eager' put after 'over' is 'OVEREAGER'.
'to' acts as a link.
(Other definitions for overeager that I've seen before include "with enthusiasm" , "Excessively keen" , "too anxious to please?" .)