Hello erin7183,
Thank you for posting in Apple Support Communities. We understand that you are having trouble with your sleep tracker showing the same sleep time every night. We would love to provide you support on this.
We would recommend checking o make sure your bed time alerts and sleep tracking settings are set up correctly and make sure the time of 9:37pm every night isn't an actual preset that needs to be changed.
Below we will include a couple of helpful resources to help you be sure that your tracker is set up correctly and functioning the way that it is designed to.
This resource tells you how to use Bedtime to track your sleep: Use Bedtime to track your sleep on your iPhone
This resource tells you how to track your sleep using your Apple Watch: Track your sleep on Apple Watch and use Sleep on iPhone
Thank you for allowing us to support you.
Have an awesome and productive day!