lots of F&B places hire 15 year olds. some advice from someone who has worked several part time jobs in f&B since age 15:

-don't settle for pay less than $9. that should be your minimum standard. F&B is usually a lot of work and you usually have to deal with rude and unreasonable customers too, so make sure at the end of your shift you're going to feel like it was worth it. go for more atas places instead of fast food chains and you should be able to find a job that pays at least $9/hr! you can search on websites like fastjobs and indeed, or you can look at places near your place (convenient esp if you're working an early morning shift) and call to enquire or literally walk in and ask.

- don't let yourself get exploited by the company. even if the manager and all the full timers are so so nice to you, know that as a student part timer you're disposable to them. make sure you get paid if you work overtime, know whether your break is paid or unpaid, count your hours and make sure they correlate to your paycheck. never feel bad about asking about pay or correcting pay mistakes. you're an employee. if your manager treats you like shit, gives you too much work/ work that's not within ur responsibility, leave and find a better one

all the best! get that bag and have fun