Summarizing the key points: legality, security, harm, alternatives. But also, address whether the site is active. So, maybe start with confirming that 9xmovies.biz could be hosting Avatar 2 for free, but that's against the law and risky. Then explain the consequences and suggest legal options instead.

I need to address the legality first. In many countries, downloading pirated content is illegal and can result in fines or other penalties. Then, the technical aspect: 9xmovies might be using torrent or direct download links. If the user is unfamiliar with torrents, explaining how they work could be part of the answer.

I need to structure this answer to first explain what 9xmovies is, the legal implications, security risks, how the site might be operating, and then suggest legal alternatives. Make sure to use clear language, avoid technical jargon, and be cautious not to provide step-by-step instructions on how to pirate, as that would be unethical.

In conclusion, advise against using such sites, warn of the risks, and guide the user toward legal alternatives for watching Avatar 2 legally.