Sure, its done all the time. Its called "topping," or "pruning." If you use the search engine and search "cloning," "topping," or "pruning," you'll find some good info on the subject.
Not necessaraly. Topping WILL produce more branches, but may not produce more volume of bud. That's because the new branches of bud will be slimmer than the main cola they replaced. I've tried topping and not topping with same-strain plants taken from exact cuttings. My production has proven larger on non-topped plants. This may not be true of everyone and every strain ... but its been proven on what I grow.