iOS 9 tries to open YouTube links within the YouTube app, but only if your app is configured correctly.
If your document contains
https://youtube.com links they will open up in a webpage like other links.
This changes when the YouTube app is installed. Then iOS tries to open the YouTube app, but fails with a "No handler found for https://youtube.com/..." alert. Additionally you will see the following log message:
-canOpenURL: failed for URL: "youtube://www.youtube.com/..." - error: "This app is not allowed to query for scheme youtube"
In order for your app to be allowed to query for the
youtube scheme you need to add a
LSApplicationQueriesSchemes key to your
Info.plist containing the scheme you want to allow:
After that you can tap on a YouTube link and an alert will appear, asking if you want to open the link in the YouTube app or not.