Hi Sthejay, welcome to planDisney!
Great idea on extending your visit! Hopefully, this will give you enough time to fully visit both parks!
You can certainly upgrade your current
one-day park hopper tickets to two-day park hopper tickets! Keep your current reservation for September 30, 2022, and stop by the
Disneyland Resort Main Entrance Ticket Booths. Let the Cast Members there know about your current reservation, and that you would like to upgrade your tickets and book another reservation for September 29, 2022. If it's hard for you to visit the Main Entrance Ticket Booths, you can also try calling the
Disneyland Resort Ticket Line at 714-781-4636 and see if they can help you there! I just checked the
Theme Park Reservation Availability Calendar and there is still availability for both parks on September 29, 2022, so you should be good to go!
I also wanted to check with you, have you considered purchasing the new
Disney Genie+ Service add-on? This is an add-on to your tickets that you can purchase, allowing you to access the
Lightning Lane entrances for certain attractions. This will help you avoid the standby lines, and should save you time from waiting in line. And as a great bonus, you also get unlimited
Disney PhotoPass Digital Downloads with the purchase of Genie+. If interested, please mention to the Cast Member that you would like to add Genie+ to your tickets when upgrading!
See ya real soon!
Jin