1) This is a really tough question. I don't think hysterical people who don't really know what they're talking about should be allowed to shut down scientific experiments. However...if the fate of the entire world is truly at risk, certainly governments should be allowed to step in and shut it down. But who in "government" knows enough about such advanced theories to give a pass or fail to such a request? And which "government" should have a say? The country that it is being hosted in? Or any country, because it's the entire world potentially "on the line" with some massive scale experiment?
2) My personal feelings, based on what little I've read on this project....sounds kind of scary to me. Not that I'm afraid of the entire world getting sucked into a pinhole sized black hole....but I sure wouldn't want to live anywhere within 100 miles of that thing when it is being used (really big booms come to mind). As for the "fate of the world" fears....my comfort lies in my faith that the God who created this world will not allow it to be destroyed until He is ready. And when He is ready, then nothing man does or doesn't do is going to make one whit of difference.