No, there is a Linux-hosted version of AROS on the Pi. Lame, very lame, as it runs on WORST POSSIBLE scenario: the Xorg nightmare, the biggest piece of **** I've ever met for a graphical GUI. A massive resource hog, unaccelerated on the Pi.
So no AROS on the Pi. Forget about getting anything usable from this hosted thing.
Risc OS is a way better OS anyway.