I have a POWER9 system actually - it has a number of shortcomings that make it not so practical as a daily driver. For one, it doesn't go to sleep and draws 27Watt at a minimum. It also has no integrated graphics which means I need an AMD or NVIDIA graphics card which have spotty support at best on POWER...
Not to mentioned it takes anywhere between 90s and 5 minutes to boot. It spends over one minute doing init including things like training DDR4 and PCI-e serdes links.