[DanBC]

In the US children aged under 9 cannot be counted as a death by suicide.

Suicide means "the deceased ended their life, and had the intent to do so". The US says that people under the age of 9 cannot make a reasoned decision about killing themselves, and thus cannot have the intent to die.

So there will be some people under 9 who killed themselves. It will be a very small number. But their death will be counted as something other than suicide.