People do carry lighter mobility scooters on tow bar platforms but you need to be very careful not to exceed the noseweight of your tow bar.
Here, a mobility scooter is secured to the BUZZ RACK Buzzpro P10 multi-purpose tow ball platform:
The Buzzpro P10 platform takes a maximum load of 75kg and weighs 12.5kg. E,g, if your vehicle had a tow bar with a noseweight of 100kg you can take a 75kg load on this platform. If your tow bar had a noseweight of 75kg you can take a load of (75 - 12.5) 62.5kg.
The BuzzPro P10 is adjustable in size, so you'll also need to check that these measurements will work with the shape of your scooter:
