@Timothy Metra Grant Cordone is both a genius, and an idiot, depending on how you want to view things. The first thing you should understand about what he is trying to do, is that unless you are making a ton of money, your chances of being audited is on the grand scheme of things very, very low. He uses this fact to his advantage because every year that he doesn't get audited, is a year in which he basically pays nothing in taxes. He pushes the law so far, knowing that even by pushing the limits he probably won't be audited and thus he will get away with it. And on the off chance that he is audited, he just has to be able to justify his taxes enough so that it's not deemed criminal tax evasion. Otherwise he simply pays the IRS what he should have owed them in the first place, plus possibly a small fine. Over the course of many years, if he is audited twice, but he gets away with it 48 other times, then financially that is a huge success because what he saved is dramatically higher than what he had to pay out in fines. This is easily summed up by the old expression, "It is easier to ask forgiveness, than to ask for permission".
As for your four bullet points.
1. Nine exemptions: He isn't saying you should claim 9 dependents on your actual taxes on Apr 15th, (that would be fraud), he is saying you should claim 9 exemptions on your W4. All this is doing is reducing the amount your employer withholds on a monthly basis in taxes. This means that at the end of the year, you may end up owing the IRS money, however his whole goal is to do other creative things in order to reduce his tax bill enough so that this doesn't happen and he doesn't owe anything. Most people claim 1 exemption for themselves, plus one for each dependent, but the form does specify that you are able to adjust this based on "projected tax credits".
4. No refunds: This is out of order but it ties into point 1. Getting a refund at the end of the year, means that during the year you OVERPAID on your taxes, this generally happens by not claiming enough exemptions on your W4. This means that essentially you gave the government an interest free loan for one year. Instead of the government holding onto that money all year long just to finally give it back to you, you could have invested that money into an investment account earning additional interest or returns.
2. Business deductions: Owning a business is probably the single best thing you can do as far as taxes are concerned. Although he doesn't dwell on it, he does say that you should try to get the business to succeed, but even if it doesn't its still beneficial because you can now claim many things as business expenses, and also have access to the wonderful home office deduction. Buying a new computer? -Call it a work computer and write it off as a deduction. Do you have a cell phone that you also use for business use? -Write off a percentage of that too, along with a part of your internet bill for that new computer of yours ect. A home office deduction can be huge as well. Because now you can write off a percentage of your electric bill, rent, heat, mortgage, depreciation, certain repairs ect or take the new simpler deduction based on the sq footage of the office.
3. 100% car deductions: Please reread my intro statement for this bullet point, because by claiming a 100% deduction he is basically daring the IRS to audit him. If they do he will attempt to justify it (maybe he gets it to work, maybe he doesn't), and if they don't audit him then he gets away with it by default. Depending on your particular line of business, a very high % could be completely appropriate and still not be obnoxious like the 100% is.
Many of his tactics stretch the law to their limit (100% car deduction), and would be frowned upon ethically. But what is ethical and what is technically legal are not always the same thing. You did mention that you were less concerned with ethics however, and more concerned with what is strictly legal so some of this stuff may work out for you although I would still suggest toning it down one notch. I would highly suggest educating yourself on some of the finer points of a few of his tactics by reading publications put out by the IRS (they actually have some pretty useful stuff that everyone can understand). Because you first have to be familiar with the specifics of what the law says, in order for you to know how to properly bend that law to your advantage because often times the devil is in the details, and as always consult a real tax professional.