Unmanned systems can fly in the NAS above 400 feet AGL via a Certificate of Authorization (COA) from the FAA. COA ops are part 91 operations and can have all kinds of limitations. Most all share two requirements relevant to this topic. First, the operator and/or his visual observer must maintain a visual at all times. This is for traffic avoidance. If he can't see the UAS and ventures beyond visual line of site (VBLOS) a chase plane is required. Second, I've never seen a COA without an associated notam.
For public use COAs, as opposed to DoD, the operators are certificated pilots; traditional manned aviators. The DoD entities I'm familiar with don't require a private pilot cert but instead stand up their operation utilizing their own DoD cert.
For a UAS at 9000, in the NAS, there should be a NOTAM on file and a manned AC flying formation. UAS of that caliber typically squawk a code and are ADSB equipped. Coms with the controlling authority is required as well. This isn't your Amazon Drone. 9000 generally warrants a fixed wing airframe. Having six props makes me think hobbyist out of his lane.
When done properly:
UAS is squawking a discrete code that they can change on the fly.
Pilot is a manned aviator
Pilot has coms with ATC and is flying his last clearance.
A chase pilot calls out any Non participating traffic that ATC can't see. On the East coast this never happens as we have radar coverage everywhere.
It's like flying an IFR flight plan under the hood with someone flying formation.
All that being said, an idiot flying a multirotor at 9000, in the NAS, without a COA, without traffic avoidance is WRONG.