Did anyone ever get blurry eyes or double vision from a slight concussion?

Yes. A concussion is similar to a bruise of the brain, and it can cause it to temporarily lose the ability to keep both eyes working together. If the double vision is constant, you should be evaluated by an eye doctor or general doctor.
Absolutely. Any time the brain is violently sloshed around inside the skull the nerve cells can be "shocked" and need time to "reset" . Some of these nerves control eye movement and thus could result in mismatching eye alignment with double vision. The vision center in the back of the brain can temporarily and partially shut down as well from a concussion.