BACK IN YOUR UBUNTU LIVE USB SITUATION
1. Launch GParted so that you are at that point of seeing all the partitions, as you showed us with the first of those shots 2 posts above.
2. Click on /dev/sda8 Grub2 core.img, so that it highlights, then right-click and choose resize, a popup window will appear, such as you have seen above.
Free space preceding will be very large. New size will show the current size of that Grub2 core.img, likely 1 MiB (if not, write the figure down). Free space following will likely be 0 (zero) currently.
3. Change the first entry, Free space preceding, to 0 (zero) and press Tab, and watch the changes. The middle field will now be very large.
4. Change the middle field to 1 MiB (or that figure you wrote down, if different). Press Tab and watch changes.
5. If all is good, you now have that large figure from the top at the bottom. If so,
6. Press the Resize/Move button, and the window will close. A summary of the Pending Operation will appear at the bottom of GParted's window. Go to the top where the icons are, and at right, the check mark/tick may be green and mouseover tip show Apply.
7. Click to Apply changes, this may generate a warning about moving data, it is non-fatal, so OK. The procedure will take some time, and at the end, control will be returned to you.
All being well, you now have a large amount of Unallocated Space, in your list, sitting directly above your /dev/sda9 Ubuntu install, and you can grow Ubuntu into that by a similar procedure.
Perhaps we will break here (you can reboot or power down and remove the stick and see that all is still working OK), and I'll proceed with that growing stage after that.