Seeing All these Perfect Susanoo make me a bit Sad that Itachi didn't get one.
How Strong and cool would it be if Itach had Perfect Susanoo?
Kakashi's using PS with his MS, so it means It's not definite anymore that Itachi didn't have one. It's more "Itachi doesn't have PS?", instead of "Itachi doesn't have PS!". Just because we never saw it, doesn't mean he still didn't have it laying in the back burner... There were exactly 0 fights in the manga where PS would have served Itachi any use. the closest fight where you could say any PS user could've sprung PS would've been when nagato used CT, but seeing as naruto wanted to teach naruto something about team work instead of doing everything on your own, using a PS then would be counterproductive.
Anyway, I still doubt Itachi had PS, but if itachi's ghost pops up in the next 10 chapters(let's be honest it won't even be a surprise) and pops PS, I wouldn't be shocked.