You're right, it's nine. EAST RING doesn't count, unless perhaps you're a circus afficionado.

I'd love to see the entire list, though I'm sure I wouldn't recognize the vast majority of the offerings. My recollection is that they were all to be eight-letter words.

The Mathematical Games column that Gardiner wrote that in is from the Sixties, I think, give or take ten years. He gave a reference identifying the individual who made the assertion and I suppose I could look it up but I haven't the initiative.