Thanks for testing. Your feedback is really helpful.
You should be able to use the d-pad by default (instead of the joystick) by toggling the analog button, if your controller has one. Also, with analog off, you can use both the d-pad and left joystick at the same time.
Because the buttons map differently for different controllers, I decided to not map start and select by default. Although it is interesting that yours also mapped to 8 and 9, same as for my PC gamepad.
Not being able to identify the start and select button on Edge is unfortunate. Likely down to Edge implementing the Gamepad API slightly differently. But I suppose you can always map those controls to some other button on your controller.
Thanks again for the feedback.