It's a probably a fair conclusion that the J will be the better sailing of the two, particularly in Chesapeake wind. A 3-4' LWL advantage is significant. That said, the Alerion is a stunning looker and would be suitable for the use you outlined. You may not like the location of the head in the Alerion, though.
One point of difference, and this is important to me at least, the J/92 has an open transom and the crew sits on the edge of the cockpit comings - it doesn't have cockpit "seats". I prefer a closed transom, especially if I would be daysailing.
I would suggest, if you like the J/92, that you also at least look at the J/100, which in my mind is probably more "daysailer" than the "racer" of a J/92. The /100 has an enclosed cockpit and real seats - ones that you can put cushions on! Some even have the Hoyt jib boom installed as an option, similar to some Alerions.