I'm no expert on rubber boots, don't own any. But Armor All is great for protecting anything rubber/vinyl against drying/cracking and UV damage. I've also used something 2001 I think. Very similar. There are other product and there may be better. I can only speak to my experience.
I wouldn't put it on the soles unless you want to spend a lot of time picking yourself up off the ice. Pretty slippery stuff.