Thank you for the tip - it solved an issue for me with a few stalled updates, plus a badge "1" remaining although all updates completed - it's been a bit haywire since just before Christmas as well. All the Best to all around you for the coming year.
I still have my "old" 5S. Since the iOS 9 update, I have experienced stalled updates periodically. Sometimes, just several aborted/ended installs with a retry will work. Other times, I've needed to delete the app and reboot the phone. It seemed to happen with larger files and, more likely, several apps are updating at the same time. Almost always, the delete and reboot solved the problem. I'd reload the app and be able to use as normal