Everything's bound to go round — that's agreed (7)
I believe the answer is:
tallied
'agreed' is the definition.
('tally' can be a synonym of 'agree')
'everything's bound to go round' is the wordplay.
'everything' becomes 'all' (all things).
'bound' becomes 'tied' ('tie' can be a synonym of 'bind').
'to go round' means one lot of letters goes inside another.
'all' placed within 'tied' is 'TALLIED'.
'that's' is the link.
(Other definitions for tallied that I've seen before include "Agreed, corresponded" , "Corresponded - kept score" , "Reckoned debt or score" , "Agreed; calculated" , "Matched" .)