You really won't be able to solve this without dealing with his anxiety first. Deal with the anxiety, and the problem goes away. Mounting something to keep him from hopping up will fix the symptom, but not the root cause, and may even cause his anxiety to get worse. (because he feels even more trapped)right now we just need some ideas on what to do to make him not want to hop up, and then we can deal with his anxiety over being separated from the other people in the house.
Scolding didn't work because to his mind, he was finally getting attention and didn't mind that it was negative, as long as it was attention- so the scolding was actually a reward. Crating didn't work because (assuming it was properly introduced) the crate is a positive place for him, not a punishment. And again- being told to go to crate is still some form of attention.
So work on building up time you are separate. Start by walking away a little bit, then staying within his view-but ignoring him, then going briefly out of sight, then staying out of sight for a little longer, etc.