I managed to fix mine by simply using Sleep++ and with my Apple Watch, simply recorded some sleep data and when it got synced to Health I could open the application again without it force closing every time
It's happening with me too, but only for the last few days as far as I can tell.
I have no idea what triggers the crashing, or what triggers the crashing to start, but as soon as it's midnight and therefore the next day, it opens properly again.
Ironically mine started to work yesterday, which was when I used the app "Pillow" to track my sleep. That seemed to fix it. After upgrading to 9.3P4 today it has continued to work as well.