This is a little bit early, but how long are the lines typically to get at-con badges early Saturday morning? I'm planning to get to San Jose between 7-8am so I won't be stuck in line for 3+ hours, but I haven't done at-con registration in a long time and I don't know how much help it would be to arrive right when registration opens.
You should be okay. If the line's anything like how it's been previous years, the crowd at that time should be on the much lighter side. It's when you get there at around 9:30 and later that the line starts becoming ridiculous (probably a 2-hour wait around 10, and even longer as you go through the day). But if you're getting there when people are just starting to wake up, you shouldn't have any major issues.