Children, perhaps, in pub: zero change for Americans (9)
I believe the answer is:
innocents
'children perhaps' is the definition.
(innocents can mean children)
'pub zero change for americans' is the wordplay.
'pub' becomes 'inn' (an inn is a type of pub).
'zero' becomes 'O' (O resembles 0).
'change for americans' becomes 'cents' (US coins).
'inn'+'o'+'cents'='INNOCENTS'
'in' acts as a link.
(Other definitions for innocents that I've seen before include "People leading a simple life maybe" , "Persons free from guilt" , "They are not guilty, like newborn babies" .)