Hi Lroth1986,
Post #2 here includes links to the better forum posts and topics about mattresses and children that should be helpful and would be the first place I would start. It also includes many links to some of the better options I’m aware of for children.
I don’t see a mattress on the page you linked … only information about their club O program.
It uses good quality and “safe” materials that would certainly be suitable for a child and would be worth considering although there are also some other choices in the previous links that I would include in your research as well. I would keep in mind that a firmer mattress that wouldn’t be as comfortable for an adult is generally a more suitable choice for a child.
Phoenix