I have app designed for the iOS 8 using the ABAddressBook framework
for the contact. In iOS 9 the Contacts framework
is introduced in place of ABAddressBook
.
To check the effect of this change I checked in the iOS 9 device and everything is working fine.
Is my understanding correct here?
Whenever an API/Framework is mentioned as Deprecated it indicates that sometime in future Apple will completely stop supporting the API's. This indicates the developers should move to the new API's soon.
In your case AddressBook Framework is considered as deprecated from iOS9 so Apple will allow these frameworks as of now(may be till iOS10) but that depends on Apple when to stop it completely.
Usually Apple stop supporting the deprecated API after a major release but there are also cases where the deprecated API's survived many major releases.
My suggestion would be move to the Contacts Framework soon.