Your ISO9001 can be completely fictitious just like the stamps and labels that say your product meets all required safety standards and approvals. If you're concerned that someone might check, just use another company's name on your product.Exactly. ISO9001 simply allows you to define the boxes that are to be ticked. It guarantees nothing.
If you're going to sell substandard products there's no reason to hold back in terms of what you print on the outside of the box.