The point still stands. Why is a 20-year-old engineering company paying you $9/hour? The coffee shop in town here pays new counter staff $14/hour. Generally speaking, one does not pay someone who is as important to the business as you claim to be so little, intern or not. Realistically, I see two possibilities:
a) You're wildly over-estimating your value to the company.
b) Your boss is exploiting you.
Think carefully about which it is. Be honest with yourself. If (a) go get the coffee like a good intern, then go back to school. If (b) ask for a more reasonable wage and/or equity (if that's your preference), in the form of a signed contract. "We'll take care of you" is worthless, no matter how trustworthy the person saying it. If they actually mean it, there will be no problem with getting a deal signed on paper.
I definitely am not absolutely critical to the success of this company, and I realize this, but losing me would still hurt them. It's really the experience and knowledge I have with them that's valuable to them, and that would be hard to reproduce with someone else quickly, especially at such a critical time like right now.
Am I stepping up my game and responsibilities as much as possible? Absolutely.
Ok, then you need to ask for a raise. $9/hour is a wage you pay someone who is completely replaceable; and even then only if you're a greedy bastard who doesn't care about your employees.
A raise could come in the form of a much higher wage, or a combination of a higher wage and equity, if you really believe in the company. You should be getting a significantly higher wage either way, though.
a) You're wildly over-estimating your value to the company.
b) Your boss is exploiting you.
Think carefully about which it is. Be honest with yourself. If (a) go get the coffee like a good intern, then go back to school. If (b) ask for a more reasonable wage and/or equity (if that's your preference), in the form of a signed contract. "We'll take care of you" is worthless, no matter how trustworthy the person saying it. If they actually mean it, there will be no problem with getting a deal signed on paper.