Being a licensed pilot, I do not think it is possible to glide @ 8,000 MPH. You could drop a titanium spear from 100,000 ft. and it would still not reach hypersonic speeds.
The only possible conclusion to this statement, “hypersonic glide vehicle”, is translation malfunction.
That is the way I understand the concept, and I will be the first to admit I may be %100 wrong about my belief in how the technology is supposed to work.