I’m a dissenter, an outlier here, the 9 items or less issue. And yes, I have been taught good grammar and know how to use it – and when to use it.
Quite apart from the matter of formal/informal language, which pedants profess to disdain, there are certain words or constructions which are almost never used informally. Fewer is one of them, and Whom is another. Those who clutch their pearls at “incorrect” use of Less, can you in all honesty swear that you say “whom” instead of “who” every time? Ever said “who can you see in that picture?” or, using correct structure, “from whom did you hear that?”
Then there’s the question of clarity, a red herring which pedants love to trail. If we have both Less and Fewer in order to distinguish meaning, please explain why we don’t get confused over the use of More to mean the opposite of both of those words. (And also how many speakers of other European languages are not painfully befuddled at not having the two expressions.)
Myself, I do use Fewer. I’m a retired teacher and it’s almost a reflex. But I only use it for certain if it comes immediately before the word I’m qualifying. Fewer apples. There were fewer children in my classroom than in the one next door, and less of them could play the recorder.
So, to the supermarket. What have I got in my trolley? I’ve got something called shopping. It’s an uncountable noun. Most of us, apart from those living in the parts of Britain where what you bring home from the shops is called “messages”, use the word Shopping not only for the act of buying things, but also for the totality of the things you buy. Surely nobody gets confused by the sentence “I nearly left my shopping on the bus”?
Why do I have more money left over this week? It’s because I bought less than usual. I didn’t buy fewer than usual. I didn’t buy less or fewer “anything” (respectively, milk and sausages, for example). I just bought less. I went shopping with Jill. I had less in my trolley than she did. Suddenly at the checkout, do I have fewer in my trolley.
I know my grammar, and 9 items or less has never upset my sensibilities. “Less items: bad, “less than 9 items”: okay. It’s a number, it’s less than 9.
9 items or less, pedants will reply to with “less what?” and I’ll respond “less stuff, less shopping, just less”
How about a compromise: not more than 9 items?