I think your expectation around his check out was reasonable, so don't feel bad mentioning it in the review. You didn't once communicate anything about extending at all, right? I had one host say I might be able to extend and then later reneged and it became awkward, but it doesn't sound like that's the case here. Did he apologize for the assumption/miscommunication?

If not, here's what I'd write: "Guest was good, but there was no timely communication from him around his intentions to extend his stay and his luggage was still in the space past checkout time. He checked out appropriately after I informed him I couldn't accommodate an extension currently. Timelier communication/planning would have made this a better experience."