If I have wheels on my car that have two bolt patterns can I just drill holes in the hubs using the rim holes to change my wheel bolt pattern? I would think it should work but just checking.

Theoretically, yes. But in practical terms, the bearing flange that you'd like to drill out and add wheel studs to, isn't going be large enough in diameter to leave a safe minimum edge distance between your new holes and the edge of the flange. As a rule of thumb (but by no means an adequate method for determining something this critical), if you plan to use a 12mm stud, then the edge of your new holes must be no closer to the edge of the flange than 12mm. As I said though, it's unlikely there will be enough material left.

Yes, it might work, or you might end up with the wheel off center and not to mention the lack of material to properly hold the wheel to the hub.

So.... I wouldn't do it. There is information about upgrading hubs and such on this forum, try searching for more info. Then have a machine shop do the drilling.