For starters, 9anime and its rebrand, aniwave, are long gone. You're looking at a fake site.

What should i use than?

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.

Try any of this list! https://everythingmoe.com/

https://fmhy.pages.dev/videopiracyguide#anime-streaming

Kissanime is still going strong.

https://addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/

This will let you download videos that play in your browser.

i thought the same... but just tried it and apparently its a no-go for this site (unless i got the wrong fake site)

nice. i like that unlike video-downloadhelper, this one is actually open-source. shame that the github repo is now archived but i'd still trust that over a closed-source addon.

i guess i'm just not into the streaming scene... i just use vpn + qbittorrent and either nyaa or dht search. but its been a long time since i couldnt find what i wanted on nyaa