MRI vertebrobasilar hypoplasia right side theres robust flow void anastomosing the basilar artery w cavernous portion of internal carotid artery/mean?

Normal variant. The arteries at the base of the brain can course in several different patterns but ultimately get the job done, that is, supply brain tissue. Your pattern is like your fingerprint. Some more unusual patterns have an increased association with aneurysms, but this would have likely been described if present and vertebro basilar hypoplasia, as in the picture, is pretty common.