I've got 2.9.5 working just a few moments ago.
Yesterday I did update Visual Studio from version 17.11.6 to 17.12.3, though that did not seem to help, but dot Net 9 seems to require this newer Visual Studio version.
This morning I uninstalled the previous version of dot NET 9 ( perhaps the one that said Desktop)
I followed the download link in github CodeProject Issues to install a slightly different version of dot NET 9.
(
Download .NET 9.0 SDK (v9.0.101) - Windows x64 Installer)
I repeated the install process of CP 2.9.5 without removing it.
After a cold reboot it is working, early days though.
edit: Though the CP dashboard was working I noticed that AI was not delivering Alert clips when a camera was triggered. I had both YOLOv5 6.2 and YOLOv5.NET modules installed and active, uninstalling the latter module Alert clips started to show again in
Blue Iris as expected.