Hello good people,
as I am working on the new WebXR API, i decided to test the integration with physics engines and have created this small demo:
https://playground.babylonjs.com/#PPM311#42
If you have an oculus quest (with webxr enabled in flags) or a mixed reality device and the latest chrome you can try it out. Just use your controllers to hit the balls and dont let them hit the goal behind you! If you are not next to the goal, teleport there 
It is very minimalistic, and the code is a bit chaotic, but it seems like the API is slowly forming 
BTW - it works well with the webxr emulator as well (recommended to all - GitHub - MozillaReality/WebXR-emulator-extension: WebXR emulator extension), but it is rather hard hitting the ball with emulated controllers