Delta already posted a waiver as of 6:44pm ET
https://pro.delta.com/content/agency...etin-1---.html
FWIW, Delta Meteorology will usually coordinate to issue a waiver once a tropical storm/hurricane watch is issued. The 5PM ET advisory package by the National Hurricane Center had a hurricane watch for the Cayman Islands, so I guess it makes sense a weather waiver was issued soon after.