Here in the United States, school bus subcontractors are often privately owned; some guy with 7 school buses in his back yard, etc. and it can be harder for them to get drivers so they are more lenient/personable and not so automatic with all the paperwork and rules.

Have you applied anywhere, even with the driver's abstract (or gotten your abstract to see what it actually says?) and maybe talked to them to see what they recommend? In X years our accidents are not on our record anymore, maybe you could work in a trucking office for awhile (since you know how to drive so "understand" trucks and trucking a bit better than others) and maybe getting to know someone better will influence a decision; could be they will have drivers call in sick at the last minute, etc. and with your license. . .