Is my dog a Miniature Schnauzer or Kerry Blue Terrier?

I'd guess he's a poodle mix before a Kerry Blue - it'd be really strange for a relatively uncommon purebred puppy to have been mis-sold as a much more common breed. They don't tend to have standing ears, either.

If by the CKC you mean Continental Kennel Club, this sadly isn't a very reputable organization, used by commercial breeders to be able to claim their dogs are 'papered', but there is very little oversight to make sure the dogs are being registered as the correct breed. If this is the case, it's possible that your pup's parents weren't purebred Schnauzers even if they were registered as such.

It'll be interesting to see what the Embark comes back with! I'd still say that, if he is a mix, poodle is more likely to be in there than KBT. Unless his breeder also bred KBT? Looking forward to seeing what the results say!

There's a ton of variation in schnauzer/poodle crosses, especially once you get past a 50/50 schnauzer/poodle cross, because it's hugely unpredictable which breed traits they inherit. But there absolutely could be something else out there as well - genetics are wild and definitely don't always produce the looks/behavior you'd expect!

He could still have something mixed in there more than three generations back - none of the DNA tests can go back that far - but definitely way more schnauzer than anything else! Just one that's off-standard - happens a lot, my poodle's the same way.