There’s no notion of ‘Full screen’ within iOS 9 or iOS 10 unless you can get your web content within a Web app or within an actual app. I’m not familiar with how Android handles this. One reason for never hiding the URL bar completely is because of security: It’s important to know what domain you are visiting.
To get full screen on a web app, you would need check the ‘Home screen web app’ checkbox in the document inspector, and also instruct the user to add the app to their Home screen by using this button on the share panel:
When they open it from their home screen it will appear full screen without any status bar.