You probably need to look more carefully at what was billed
https://support.apple.com/en-us/HT201382
AppleTV+ is $4.99/month after a free trial period.
$8.99 doesn't relate in any way to AppleTV+, but it might reflect a purchase made (e.g. a movie rental or similar, that's outside of the AppleTV+ service).
It could also represent an Apple One subscription (which includes AppleTV+ amongst other things), but the numbers don't quite add up there.
It could also be unrelated to your AppleTV and be an App Store purchase you made on your phone or your Mac.
Lots of options. But I doubt Apple deliberately misleading you over Apple TV+ subscriptions is the root cause. Can you imagine the media outcry if that was the case?