How do I handle a long gap on my résumé? after 9 years as a school bus driver

I have been out of work for 4 months and worry about the gap. I am in Spokane, in case local advice matters. I have done some volunteering and a course during that time. What do you say in interviews?

I was hired after a 4-month gap. The manager said the skills test mattered more than the dates.