The 1st RAC one is the one i bought about a yr ago and its pretty good, i have no complaints really with it. It has a socket to fit the variator nut in the box but not one for the clutch nut. I just use a normal socket for the clutch and its been fine. Like you say tho its only 12v and NO your agility battery wont power it, well mine wont even if i run the scoot. I connect my car battery charger leads to the leads for the wrench. and then i can power it off the mains.
If you dont have a charger to power it you may still be cheaper buying a cheap 12v car charger and the RAC one?