iirc the no windows 9 thing was actually because a lot of software ran a compatibility check like:
<span style="color:#323232;">if windows version = “windows 9*” then open legacy mode
</span>
This worked for software written for newer windows like xp but still allowing a legacy mode on older windows versions like 95 and 98. Problem was this also put that same software running on windows 9 into legacy mode. So they called it windows 10 to sidestep the compatibility issues.