Yes instant clones are supported. Only limit is that you have to create all clones upfront and disable auto reboot as mentioned in the doc.
how is it possible to test with view planner "local run" when the instant clones are always joined into active directory?
I did not understood your question correctly, can you elaborate?
However, here is how you can do local run with instant clones:
1- Create your golden VM with applications and View Planner agent installed, enable auto login.
2- Create your instant clones using golden VM, join them to active directory if needed.
3- Disable force reboot from harness bye setting by setting VM_FORCE_REBOOT to 0 in configuration.
4- Create a local run profile and start run.