Here's what I got from an email from HPD firearms department
"Aloha,
Thank you for your patience.
The online registration is backlogged 4-5 weeks. You cannot use the firearm until you get the registration in an email from HPD. If you want the registration sooner you can come in person, no firearm needed, to register. You will need the information on the firearm, a picture/copy of the permit, and a picture of the serial number off the firearm.
If you have any questions please call (808) 723-3188"
Funny thing, it took me less than a day to purchase a handgun and take it home, but I can use it for another 2 to 3 weeks🙄 unless I go to HPD to register the gun in person.