I'm hoping to get an opinion on my dog's behaviour - I'm not sure if what he's doing is "normal" or not.

He's a 11 month Cavalier x poodle, unneutered, owned since a puppy, who becomes very vocal when I leave him. We're talking high-pitched whining and pacing.  This happens if I leave him but other people happen to be in the house, and it takes him quite a while to calm down. It also happens if everybody in the house leaves, but in this case he calms down much quicker (we've videoed him).

He is crate trained, and I crate him with something tasty before I leave. Usually he ignores the tasty thing and whines because I'm getting ready to leave. (I also try to crate him at other times so that he doesn't associate it with me leaving him.)

Wearing him out before I leave him does tend to alleviate the problem somewhat, but all other dog-owners that I've spoken to look a bit perplexed that I have to wear my dog out before leaving him. Is it not normal to have to de-bounce your dog before leaving them?

Usually "wearing him out" involves an off lead/long line run around a field for 40 minutes-hour. Possibly with some training thrown in.

It would help us to know a little more.  How often and for how long for instance.

Isn't there room where he can have some freedom and space to move ?. Could you not leave the crate door open so he can go in it of his own free will rather than being shut in there ?. Personally I hate the things, the thought of an active dog being trapped and frustrated in one I find awful. Not saying you do but I know too many people who leave dogs in crates for far too long, that are often far too small and I find it really upsetting, but they feel its an easy option if they haven't housetrained properly.
Maybe your dog just associates the crate with being left alone.

I have heard of people putting something in a place (usually the middle of the floor) that doesn't belong there. A vase, a box, anything. What you do is put the dog in the crate, put the article on the floor, or somewhere the dog can see it, then walk out of the room. Ignoring the dog completely. You go out, then come back in and remove the article. Once it is out of sight, or back where it should be you then speak to the dog. Calmly. Start with short periods, then gradually build it up. The dog then realises that the 'thing' doesn't belong there and you will be coming back to remove it.

By 11 months, we don't use a crate, other than overnight because we rent and I'd rather not have unexpected surprises happening while I'm sleeping.    Before about 6 months, mine were crated, in the kitchen when we went out (for the same reason - renting) but for no longer than 4 hours absolute maximum.    Now they both stay in the kitchen, with a baby gate across the doorway so they aren't behind closed doors but are still confined and not given the full run of the place.

It helps to 'debounce' LOL him before you have to leave him, that's not strange although may not be necessary for all dogs.   I guarantee you however, that this release of surplus energy won't last long so if you are away for hours, what he's doing is to be expected.    I'm all for using crates, as an aid to keep puppies safe and out of mischief, but too often these days, dogs seem to be spending far too long in a crate so small wonder they kick off.

I'd suggest you try confining him to a dog-proofed room rather than crating him, especially if you are leaving him for a long time (4 hours is the norm, on a regular basis, during the daytime).   If you are away for longer, I think you may be looking at having somebody come in to take him out for a run during your absence, or finding a day creche for him.

I'm afraid there are signs that dogs left alone at home are more and more in trouble.  A recent prog. I watched where 40 dogs were video'd at home.   6 appeared to be okay.  6 were showing signs of stress and the rest paced, barked, howled, messed and were destructive.  To the point when their owners were shown the results, they were shocked - some wept.   They thought their dogs slept while they were not there, like they do when they were home.   Not so I'm afraid.   When the pack leader(s) are away, dogs don't totally rest.