It could be 2yo grain whiskey, I suppose. But the other 90.91% would have to be whiskey aged at least three years.
I think Davin also pointed out this 9.09% exists so that Canadian producers can put in an American produced product and get some tax advantages. I suspect that this is where you'd find the rumored S-W bourbon in the higher-end expressions of CR. Or maybe LDI-produced 2yo rye. Or maybe older LDI rye (I believe I've read that Diageo has older rye they've purchased from LDI that continues to reside on LDI premises).