As per the court’s ruling Whatsapp cannot share data collected before 25th September with Facebook. After 25th the data can be shared by Whatsapp even if user has opted out of the service. If a user has accepted the new terms and conditions, still older data collected before 25th September cannot be shared.
The honorable court allowed Whatsapp to retain message (some kinds) to assist user with their services. The Court also asked government to look into Statutory regulatory framework for IM clients.
So if you are using Whatsapp do note that none of your older data will be shared until 25th September, but after that WhatsApp can share your data with Facebook and it’s group of companies for marketing purpose and for commercial advertising.