Region where piñata is smashed, divided by a crack (9)
I believe the answer is:
patagonia
'region' is the definition.
(Patagonia is an example)
'pinata is smashed divided by a crack' is the wordplay.
'is smashed' is an anagram indicator.
'divided by' means one lot of letters goes inside another (inserted letters divide the word).
'crack' becomes 'go' (to have a crack is to have a go or turn).
'pinata' is an anagram of 'patnia'.
'a'+'go'='ago'
'patnia' placed around 'ago' is 'PATAGONIA'.
'where' acts as a link.
(Other definitions for patagonia that I've seen before include "Region of South America" , "Region of southern Argentina and Chile" , "Craggy region" , "Southernmost region of S America" , "part of South America" .)