The minimum age is determined by certifying agencies. The 2 most used agencies are PADI and NAUI. PADI's minimum requirement is 10, but if you are younger than 15, you will only receive a "Junior Open Water Diver." NAUI's minimum age is 12.
9 - 12 depending on the agency you are certified by such as PADI or NAUI. PADI I believe is 9, but in my opinion is not as thorough on teaching safety skills. NAUI is 12 and is what my son was certified by. There's alot to be aware of while diving to keep you safe and your diving partner safe. The more thorough your training, the better off you'll be and the better your diving experiences will be.
They take scuba lessons from a certified scuba instructor.
Common Agencies: PADI IANTD NASDS TDI/SDI SSI NAUI GUE
As far as I know, No you do not.
You have to be 15+ for the Open Water Certification or if you're 10-14, you can do the Junior Open Water Certification. It depends if you have good physical health.
This depends in most areas. In the US, you can scuba dive at 14 and get a Junior Scuba Certification, but you would need a certified adult with you. However, at 16, you would get a regular certification. In the Caribbean, you need to be 16 to scuba dive. In other areas the age limit depends, but in most places it is around 14 or 16.
SSI (Scuba Schools International) and NAUI (National Association of Underwater Instructors) are two very reputable certifications, NAUI more than SSI, which is not accepted in some parts of the world. Also, SDI/TDI, IANTD, CMAS, and others, though some, like IANTD, specialize in tech/cave training.
There are a number of "certification" agencies that train instructors to teach diving...some of them are PADI, NAUI, SSI and others. Any scuba diving store/facility willl have instructors who have been trained and certified to teach SCUBA diving. The training includes theory, practice in pools, and testing to certify that the students can perform diving in a safe manner. To try to answer the question simply would not be responsible - however, if you visit any certified SCUBA shop they WILL answer and describe the process - plan on investing about 30 minutes for the explaination, but most facilities will describe the process in a very responsible manner.
If you are not certified No you cannot rent scuba gear
Depends on the persons certifying agency. It is different for PADI and NAUI and ...... and within each of those certifying agencies, they may have different credentials that may allow diving, but with certain limitations such as MAX depth, or has be with a certified adult etc.