Completing the kundalini will NOT make you a genius if you are not one already. This guy you met is exaggerating if not outright lying. What it will do, though, is help your brain/mind run more efficiently. So, if this guy was befuddled, and mentally lazy, the energy of the kundalini would seem like it kicked his brain into overdrive. Think of it like putting high octane fuel into your car. The capabilities of the car don’t change, but you can get more out of it because it is running at the top of its capacity, compared to if you filled it with fuel that was full of additives that left particulates in your engine.
Kundalini can also increase the physical strength of your body, because your nerves and muscles are pumped full of oxygen and blood. If you want a very good idea of the possible effects of the kundalini from a Western perspective, I recommend Path Notes of An American Ninja Master by Glenn Morris. He went through the kundalini using Nei Gong and explains the effects he experienced as well as those of his students. he also covers the possible problems you might encounter.
Edit to add: Be aware that everyone is different, and has different capabilities and the energy of the kundalini will enhance any skills you already possess and possibly bring out latent talents, but it will not give you something you do not already have,