I can run shaders on v 3.8 and 3.86 but not on 3.9

why is that?

I also tried 3.88 but don't run either.

probably because of the new shader work thats been done, such as RTRT, make sure to disable everything on that tick box except 'shaders' to test if that works, and you may want to update your drivers to get them all to work again.