VTK_MODULE_INIT in 9.0.1 ?

VTK provides its usage API as CMake code and a CMake API. Other build systems would need to figure out how to utilize VTK’s autoinit system on their own. It doesn’t change that often, so doing the “see what VTK’s CMake API does and copy it into a static header in my project” is probably sufficient.

As for the error you’re seeing, it looks like VTK::CommonCore is not a target at some location. Could you please provide the full callstack?