In which case, using
Occam's razor, we can assume that there no such thing as destiny.
According to the dictionary definition of Atheism, yes, you can still believe in destiny, because it doesn't necessary require any theism. But usually one could assume that those who are atheist are also skeptical towards other claims which lack evidence and have nothing which hints to their existence, destiny being one of them.
I see no workable mechanism which would allow for destiny (other than the trivial stuff like "you're gonna die, it's your destiny, lolz"), so there is pretty much no reason to believe in it. I also fail to see any advantages of believing in destiny despite the lack of evidence.
Also, about my previous examples 2 posts ago: Way to miss the point.
In example one, belief doesn't matter. Say this person demonstrates or otherwise proves that he indeed does have these powers. It's about theoretical free will vs realistic free will.
In example two, the 2nd question, "is it their own will?" wasn't answered. It's not really free will when it's controlled by someone else, is it?