There is now a genetic connection between your DNA submission (Y-Search 9BCZF) and the South Carolina Casey DNA submissions. Both lines share the following L226+ off modal DNA mutations: 534 (15 to 14), 393 (13 to 12), 458 (17 to 16) and 449 (29 to 30). Another earlier Casey cluster has the L226+ off modal of 534 (15 to 14). All L226+ submissions have early ties to southwestern Ireland and L226+ is a very recent Y-SNP mutation that happened around 1,300 years ago.
This means that the Kersey and the two Casey clusters all originated in southwestern Ireland as Caseys. One branch remained in southwestern Ireland for many centuries and many descendants migrated to the US in the late 1800s. The Kersey line migrated to England as early as 1600 were known as Kerseys (probably changed name to be more English sounding). The South Carolina Caseys were living in the US by the early 1700s and are a genetic branch of the Kersey genetic line. The Kerseys may have migrated to the US as Kersey or Carsey and later changed back to Caseys. DNA testing is really revealing a lot of information on the Casey and Kersey lines. For more information, see the Casey DNA Project web site: