Hard and fast rules are best for those who don't want to think. I challenged the hard and fast rule that student divers do not use dry suits. My son did his open water training in a Viking dry suit - he was always too cold in a wet suit. And if your son is not capable of rescuing you, dive in a group of three - but you have to vet the third diver. We also broke the hard and fast rule of only diving in pairs. Bottom line = expect a lot of resistance to breaking the rules, especially if you question the justification.
How silly.
There is no "hard and fast rule" about students in dry suits.
There is no "hard and fast rule" about diving in pairs.
Minimum age for scuba certification is 10 years of age. Certifying someone younger than that is a violation of standards. That's "hard and fast."
(Frankly, hard and fast rules - scuba or otherwise - are typically put in place to protect people who can't or don't think from harming themselves or others.)
---------- Post added September 20th, 2013 at 10:50 PM ----------
If that's your standard for letting people dive, basically any child and many adults would not meet it.
Divers need the physical and mental skills necessary to perform the actions that may be required of them on a dive - both uneventful and emergency situations.
Further, divers need to have the intellectual AND emotional capacity to understand and accept the risks/consequences they are assuming.
All divers fall somewhere on a spectrum for both of these variables. Adults have the "advantage" of being allowed to accept risks/consequences for themselves... irrespective of their actual diving skills.
It would be atypical, but not impossible, for a 9yr old to have the requisite mental and physical skills to dive and be an effective buddy.
However, the likelihood of a 9yr old having the necessary intellectual and emotional capacity is infinitesimally small. Personally, I feel that any adult willing to put a 9yr old in that position either does not understand diving or is just plain irresponsible.
Of course, some will say "But does that magically change on a kid's 10th birthday?" My answer is "Of course not. 10 is too young as well. As is 11, 12, 13, and for many so is 14." (And yes, there are many adults that lack the skills, intellectual ability, or both to dive. If that's the case, those people should not have been certified.)