If the dealer ordered the car whilst it was still on the scheme, then you will receive the car even if it leaves the scheme.
There has been the odd case where a manufaturer has left the scheme completely and in a few cases people didn’t receive their order, but there’s no indication that KIA will leave.
Unfortunately, there has been some people who ordered the Sportage (not via Motability) as early as February and have been told to expect it by May next year. But they could receive it much earlier.