There are really no words required for the spectacular views that you get at Kinnoull hill (especially when it's sunny).
This walk is really all about the scenery, if you're after a good trek you should pick somewhere else to go to. I'd 100% recommend paying Kinnoull hill a visit though if you deem things suitable for yourself after examining the pictures below.
In my opinion, those who use electric scooters or certain types of electric wheelchairs should manage if they take care. If you go when the weather is more fair it will be far more manageable on the 1.5Km walking route.
The car park is a very good size and you shouldn't have an issue getting a space. But there are no specified accessible bays so you'll just need to park in a wonky fashion in order to command more space.
One negative is that there are no toilets available. I'd suggest just searching for the McDonalds in your google maps which is a 10 minute or so drive away and has an accessible toilet.
If head down to the bottom of the car park you come into a small sitting area with a map of the surroundings. Take the opening on the right, carefully cross the road, and follow the path.
The surface of the path is quite gritty/stoney and there is a gentle incline as it makes its way round the hillside.
The beautiful views become obscured by trees as the inclination of the path increases significantly at parts and the surface of the path becomes less gritty - thus leaving you a dry dirt path (on a good day).
Like I said most scooter/electric wheelchair users should be ok but care must be taken. Hopefully you would have people there to support you if need be.
For those who walk but are less mobile, there are a couple of benches spread out on the 1.5Km route to the hill summit. Due to the surface of the path I'd imagine it might feel a bit loose and unstable underfoot. Also there are one or two short, sharp inclines which are another challenge.
It is for you to judge. But if you were in the area it'd be great you went and just tried it out. If you begin to find things too difficult, then just turn back. Instead, the pretty sitting area next to the car park would be nice for you to have a picnic.