I have been thinking about this. There was a Raptor Systems Talos II Lite motherboard at the Xilinx event with a Xilinx Alveo.
The bigger concern/ issue I have is simply that the cost of Power9 systems compared to what you get makes it hard to swallow.
I also asked the IBM Power team at Hot Chips 30 (including a STH reader at IBM) and I was told that these are viewed as "toys"
I am always down for playing with different tech. At this price point, it might be a lot of fun.
...But then reality kicks in. What would I use it for? Do I really need another Linux box around the house? Can this do something that an x86 box can't? What does it offer over a used Power7 eBay special?