how do i find my magazine subscriptions on my iphon 6s with ios9?

If you had the magazine when you upgraded to iOS 9 it should have been automatically moved from the old Newsstand App to a folder named Newsstand. If you don't find that and can't find the magazine app elsewhere, try search (drag down with one finger starting somewhere in the middle of the home screen) and search for the magazine name. If it isn't found you can download the magazine app again from the App Store.