that is not how those statements work or why they are made.
products labeled disinfectants are regulated by the epa. manufacturers provide data for disinfectant efficacy over specific subsets of microorganisms and quantify their ability to reduce those populations under the conditions they suggest the product be used (concentration, time exposure, surface type, etc.)
if it says 99.99%, it means it was able to reduce some subset of microbes population by at least a log(4) fold under those conditions.
here is an example for a lysol product.
you can see for this one product, their data supports the claim
"kills
99.999% of (Enterobacter aerogenes) (and) (Staphylococcus aureus) in 30 seconds"
while only claiming
"Kill(s)
99.9% of E.coli O157:H7 in 30 seconds"
those claims are based on data. the product absolutely does not kill 100% of the tested microorganisms in the time frame suggested. And it certainly doesnt klil 100% of all microorganisms that exist and werent tested.