I have the HW-Q70T soundbar, which sounds great. I just added the SWA-9000s, and when I use my phone in Bluetooth, there is sound coming from them (not loud, but it's there). But when using my TV, with ARC, and do a Dolby 5.1 test on YouTube, only the soundbar produces sound (not even the sub makes any noise).
I have tried through my Roku Ultra (which is set for Dolby output), and direct through the apps on my Sony Bravia. My Sony's sound settings are set for Dolby as well. The Sony is a 2017 Bravia XBR900E.
Maybe you have to deactivate passthrough mode on your tv or even better, youtube just outputs stereo and so the 9000 are not used. Make sure that the bar is not on standard setting but on surround or adaptive ... standard also just uses the bar and not the 9000