No need for a notary, no need for "the can't be counterfeited form" from the state.
(a) Serologic confirmations of immunity to measles, rubella, mumps, hepatitis A, hepatitis B, or varicella, are acceptable. Evidence of measles, rubella, mumps, hepatitis A, or hepatitis B, or varicella illnesses must consist of a valid laboratory report that indicates confirmation of either immunity or infection. (b) A written statement from a parent (or legal guardian or managing conservator), school nurse, or physician attesting to a child's positive history of varicella disease (chickenpox), or of varicella immunity, is acceptable in lieu of a vaccine record for that disease.
That is not an opt out. That is to provide wriiten documentation that you already had that particular disease (and lived) so you are now immune.