So what they can do is just add tax up to the nearest 10 cent increment. And it really wouldn’t be a tax - it would be a glitch fix.
It’ll just round, like it already does. Most sales tax rate don’t actually result in clean pennies anyway. The big question is will they bill differently for non-cash customers, since debit cards don’t really care about pennies and nickles. If they don’t round for non-cash that’ll hasten the demise of physical money.