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For starters, 9anime and its rebrand, aniwave, are long gone. You're looking at a fake site.
What should i use than?
Try any of this list! https://everythingmoe.com/
Really? Hmm they seem to still play anime.
https://addons.mozilla.org/en-US/firefox/addon/hls-stream-detector/works for most streaming websites
yt-dlp supports a ton of sites (not just youtube). It's a command line program but there's a lot of different GUI frontends, like Seal (Android) or Parabolic (Linux and Windows).
I don't know if it supports the site you wanna use (someone else already said that 9anime was shut down, so the site you're using is likely a fake and you should use another one) but there's this list of supported sites.