I must admit I'm not a guru on battery chargers but it sounds like I've got the same charger as you have. Didn't yours come with the extra wires that you can attach to your battery permanently so you don't have to access the battery charger all the time? If you don't, you should be able to get some from *** Smith or Tandys or maybe your nearest scooter shop.
I know the X9 has many more electronic gismos than the X8 so maybe one of these is draining your battery.
If you luck out on the extra battery wires, I think I've got a spare set at home that I can probably mail you.
See how you go. You may just have a dud battery which of course is annoying.
If you have time to hesitate, then you're already too late. Ride safely everyone.
Piaggio X8 250ie