In any case, iOS 9 now gives you the option to ungroup this app-centric view in the Notification Center, and reassemble them by the order they are received, so your most recent alerts are always front and center, instead of constantly being pushed out by app groupings. Here's what you need to do to get to the chronological alerts view on your iOS 9-laden device:
1. Go to Settings>Notifications;
2. Choose "Recents" as the sort order in notification view;
3. Turn off the "Group by App" slide switch, and your notifications will be rearranged from the app grouping order you see in slide 2, to the chronological order in slide 3.