I purchased some saddle bags for my A125 a few months ago. I already have a top case but knew I wanted to be able to travel longer distances in all types of weather and camp with the scooter (I also do not own a car of any kind and sometimes need a way to carry more stuff) so I went for some large saddle bags. I cannot remember the brand name at the moment but they ran about $130.00, which isn't really necessary for someone just looking to carry some extra stuff on a daily commute or weekend ride.
I did a lot of research prior to buying them and was most concerned about he fit and how to attach them securely since the A125 doesn't have a metal frame, like a motorcycle, to attach it to. It seems like anything with the double Velcro strapping that is to lay across or under the seat will work and most saddle bags come with some sort of strap attachments or clip points that will let you fine tune the fit and secure them to the scooter.
The ones you included a link to look like they would work fine. The ones I have are larger and do not interfere with the tail lights at all, although I didn't believe it just looking them over in the store but the shop I purchased them at allowed me to put them on the scooter while shopping to make sure they fit before buying.
I have not used the saddle bags much since buying them since the weather is warm and I don't carry as much gear but I do intend to take some trips this fall and hope they work out as well as I think they will. I'll post about them when I have some more experience with them but as far as fit goes, I think most saddle bags will work on this scooter.