Thanks for answering my questions.
It absolutely sounds like you have the perfect example of a poodle mix on your hands. This breed of dog, possibly more than any other breed excluding terriers, is infamous for their energy, hyperactivity and habit of getting themselves into trouble. The problem lies in the fact that your dog, I believe, has way too much free time on his paws and not enough to do with it. I do a lot of behavior modification with pitbulls, which are also known for getting themselves into an obsessive mode when they are left to their own devices.
The first thing you're going to need to do with your boy is get him on a strict regimen of exercise. I understand that you have a busy life and things to do, but dogs NEED to be exercised every single day, and I'm talking more than a quick walk around the block. A youngster like yours needs a couple miles a day to drain his energy and keep him from getting into trouble because he's too wound up. If you're unable to walk him yourself, you might want to consider hiring a pet walker. In my neighborhood, I live close enough to the colleges that I put up fliers at the schools and hired some of the track runners to take my dogs for a run on the days I can't. I pay them $10-$15 bucks a day, and it really, REALLY works. The dogs get the exercise they crave, and the students get a couple bucks in their pockets for doing something they would have done anyway (the running). Several of my runners say that they feel safer running some of the woodsy trails around here because the dogs 'look' scary enough to ward off anybody who might bother them (luckily the strangers don't know that my dogs are all big marshmallows!!). Granted, you may not want to hire long distance runners, but even older people, who walk every day, could be an option.
Secondly, you might want to consider clicker training your dog. This involves buying a 'clicker' which has a little metal plate in it. You press the plate and the thing clicks, then you give the dog a treat immediately. Soon, the dog learns that the click brings a treat and will usually drop whatever they're doing in order to come get the treat. You can see more about clicker training here:
I also tend to use a back-up strategy: diversion. Instead of hollering at your pup to drop whatever he has or chase him, call him to you and reward him for performing a desired behavior, like sitting in front of you for a moment or fetching his favorite toy. Of course, this works best if he has a very favorite toy or treat that he's willing to give up the obsessive item for!
I know it can be frustrating to deal with this problem...but you also need to remember that your little guy is still very much a youngster. As a general rule, poodles maintain some of these problem behaviors much longer than other breeds, so getting it under control now, rather than letting it get worse as he gets older, is the key.
I hope this helps!!