Although the news was spotted via VentureBeat, Google has also shared the information on their Google Developers Google+ page that iOS apps will have deep links to their content appear when people do a Google search in Safari, as long as everything has been setup:
App Indexing is now compatible with HTTP deep link standards for iOS 9, as it has been on Android from the beginning. That means that you can start getting your app content into the Search results page on Safari in iOS, simply by adding Universal Links to your iOS app, then integrating with our SDK.
With this improvement, we will no longer support new integrations on iOS 7 and iOS 8. Users will start seeing your app content in Safari on iOS at the end of October.
According to the post, the support for deep linking within Android will continue on as planned:
And, of course, on Android, you can still get your content into the Search results page, autocompletions, and Now on Tap by adding HTTP deep links and integrating with the App Indexing API.
For more information, check out Search Engine Land’s page on Google App Indexing and Google’s own guide to app indexing.