How do I handle a long gap on my résumé?

I took time out to care for a family member after working as a customer-service rep. I have done some volunteering and a course during that time. How did you handle it on your résumé?

I was hired after a 9-month gap. The manager said the skills test mattered more than the dates.

I listed the volunteering and course under the same dates and kept the explanation to a sentence in the cover letter.