Yes, we've been working with the i9.
Something to keep in mind:
While the i9 CPUs are fast, you only get the higher number of PCIe lanes (44) with the 7900x ($1000).
The 7800x ($400) and 7820x ($600) both have 28 PCIe lanes.
When paying $600 for a CPU, I don't like having this limitation.
The 6850k ($500) has 40 PCIe lanes.
If your build is simple, 28 PCIe lanes won't be a problem.
Multiple video cards... or multiple PCIe x4 SSDs is where you start chewing up PCIe lanes quickly...