Renting a car and driving question

Hello everyone!
I am planning on coming to Bahrain for a summer internship in June. I spent a great amount of time researching various aspects of life in Bahrain, as well as I read a lot of topics on here. So here are the questions to which I wasn't able to find an answer for.

1) So I have a Californian driving licence (no international driving permit whatsoever) and a Russian one, would I be able to rent a car for six weeks on a tourist visa? I read somewhere that it depends on visa type if I would be able to drive or no.

2) Here is the main one: most car rentals require renters to be of age 25 and older, yet I would still be 20 during my visit. Is there any way that I could rent a car from some small local company? doesn't matter much which car, just that it has an AC. I went through the websites of "Tooranco" and "Marschall rent a car", and there is no information on age requirements.
I would even be able to pay some extra if there is a possibility to rent a car.

3)So, just in case I won't be able to rent a car, how is the public transportation? Assuming that I would live in Juffair and work in the Financial Harbour, how hard would it be getting there and back every day and getting around for food and what not on the overall without a car? Would be great to know how realistic it is.

4)How is it with sim cards and internet data in Bahrain? I read somewhere that Bahrain has pretty cheap options in terms of sim cards with lots of data. I rely a lot on maps, so I would need internet to get around.

I would greatly appreciate any insight or suggestions on the matter!