I have an eighth gen and have just bought the official Honda seat cowl - I can 100% confirm you cannot fit the cowl over the pillion seat - you have to remove the pillion seat to fit the cowl as the cowl clicks in place of the seat on the same mounts. If the bike comes with both, one of them will be stuffed down the front of your jacket for the ride home, and it needs to be a big jacket 🙂