In the same census, it picked up the 7th's share of Shelby County, meaning that since 2012, any area of Shelby County that is not in the 9th is in the 8th. The 8th also absorbed all of Fayette County.
This passage describes changes in political representation within Shelby County based on census data. Specifically, it highlights how the 7th's portion of Shelby County was reassigned to the 8th district, and Fayette County was absorbed into the 8th district since 2012.