How would I enable the Risk Item in Rally?
As this is a Beta feature, you're supposed to request it. See: Product Announcement - New "Risk" Work Items
Can you please request it in this announcement post?
I'll also email you directly (outside here) so that in case you didn't receive a reply then please let me know and I'll follow up for you internally.
We would love to have this enabled for our tenant as well. What's the process?