I got L. I’m between 8-9. I would not size up or down unless you have a larger bottom. These were very comfortable and I ran around the house in them just to verify. The cut is great but I had a bit of a seam showing under my jeans. No digging at the waist but I only tried them over another pair so they have not been washed or dried to verify that they won’t shrink. So far I really like them.
Rated 0 on a scale of minus 2 to 2, where minus 2 is Too Small, 0 is True to Size and 2 is Too Large