I have 2 objects, 1 stationary and 1 moving. I want to be able to find a point 90 degrees to a line joining the two objects at a given distance away. Is there an easy way to do this using vector math?

You may want to use a Cross product. There are an infinite number of perpendicular lines to any given line in 3d space, so to find the right one you’re looking for you’ll have to put it in context. If you want it perpendicular to that vector and the world up you would use Vector3.Cross(vectorToObject, Vector3.up)