And I wanted to buy a home cinema system tomorrow but my TV does not support any of the hdmi connections I need for it. Just so normal, here's my question, can I connect the home theater system to the hdmi in connection with the xbox so that the sound arrives at the system?
That's fine.
You can also use the optical Toslink sound connection of the XBox. Here the sound is better than via HDMI
There are certainly adapters. Then you can connect it to the TV. Otherwise I know about the One S.