Hi Jace
I grew up in SoCal too, and my mom has been a high school teacher going on 25 years.

First, your school is REQUIRED BY LAW to keep you in an emergency until one of your emergency contacts can pick you up. Chances are you'll either be in the classroom, or in the event of a big quake, the gym or on the fields. To me, that means there's no point in carrying cash since you won't be spending it.

Maybe a heatsheet in case you're stuck outside at night. A chemlight or two in case it's dark or a small flashlight. A few power bars, a water bottle are both OK. And to be honest with you, when I was in jr. high, I carried a small swiss army knife Classic (the real basic $10 one) and never got bothered. It's small enough to pretty much disappear anywhere you want to put it. And if you do get caught, and sent to the principal, playing the "I'm a Boy Scout, here's my whittling chip" card will most likely get you out of any trouble. I'd skip most other stuff, since honestly, the school is also required to care for you! If your school lets you have a cell phone, carry it, but leave it off! (My mom's personal pet peeve)

As for Jim, I think he's in college, since I just sent him college level stuff. Most of what he's talking about you can't carry (a crowbar?). If you've got your first aid or safety merit badge, and you feel OK doing first aid, go right ahead and carry a small kit. The teachers might not let you actually do any though. In a disaster, CPR isn't done, so I wouldn't stress it.

PM me if you want to discuss it more. (Former Eagle Scout too)