Answer:
I would say its not a huge deal to say either. I have heard many a ship/boat operators, Masters, Commanding Officers, Skippers and whatnot refer to themselves affectionately as a "Ship driver" or a "Boat driver". I am sure there are more than a few "old salts" out there, who by the very grumpy nature, would object. Also IMHO steering or acting as a helmsman is only one part of the operation. Driving the boat would be all of the things you need to know, such as navigation, rules of the road, stability and so on.
I guess I am one of those Grumpy old salts. A traditionalist would say that the word drive when used in a nautical context has a bad connotation, generally meaning out of control, as in "driven ashore", the current drove it down the river", "driven by the wind" and so on. The propulsion system is also often referred to as "the drive". I do not like the word drive when used about boats because it implies that it is as easy as driving a car. Traditional language uses steered, or at the helm (as in he was at the helm), at the wheel or tiller, or in regard to sailboats, "sailed". Most Nautical dictionaries do not even have the word drive in them in this context. Frankly, among people who have a lot of experience with boats, using the word drive to mean in control of the boat, reveals that you are a novice. If you don't care about that then it doesn't matter. We all learn by experience. I would suggest getting a copy of Chapman's Piloting Seamanship and Small Boat Handling if you want to learn as much as you can about boating.
However, with the huge growth in popularity of boating, the word drive has become more common, mainly because new boat owners didn't learn the vernacular. The word drive has been picked up by the media and most mainstream boating publications now use it. So it's your choice.