If flying from HNL there may not be an agent there to accept your bags more than 4 hours before departure. If there is, and the kiosks there print bag tags, tag it yourself and take it through the bag drop line. From my (one and only experience) trying to check a bag early, the kiosk will print tags before the 4 hour mark, but the tag must be activated by an agent. If they don’t but agents are working, you can always try saying you want a couple extra hours of vacation and agree to release them from delivery fees or delayed bag claims if the bag doesn’t make the flight.