The rules state it can’t be a link to a third party site and that it must be hosted in itch, I don’t believe you can host a scratch game on itch, so I would think no.
Yes, you can actually export Scracth games to other formats, using a variety of methods. One of the easier ones (and the one I use) is the TurboWarp packager. It is extremely simple to use, and it allows for addons exclusive to TurboWarp, like, for example, the 2D physics addon from the TurboWarp Extension Gallery (the only place you can really trust for you extensions, since the TurboWarp team personally tested each one and confirmed they are safe and quality) as well as stuff which could mask a Scratch game as something made in another engine. You can export it as HTML, and other formats.
