[wichtounet]

You can write a kernel in pretty much every language. There are some experiments with Rust: http://www.randomhacks.net/bare-metal-rust/

There are several reasons to choose a language rather than another. I personally don't like Rust at all, so I don't see any reason to use it, neither do I see any advantage in using it. But that's only my opinion. A lot of osdev currently is made by hobbyist (not counting the handful of really succesful kernels), so the main argument is simply personal and there is nothing wrong with it. Moreover, keep in mind that Rust is pretty new while C/C++ are decades old, this means more support, more portability, more people that know how to use it, ... This is not negligible at all.

[nickpsecurity]

Forget the experiments. Try this one:

https://www.redox-os.org/