CKEditor inline toolbar position

It does not have a configuration option for this. There are only four options for the X,Y offset in pinned and docked modes - e.g. config.floatSpacePinnedOffsetY.

The only idea that I have is implementing your own plugin like Floating Space, or modifying the current implementation.

And as the last resort, you can use the Shared Space plugin to place the toolbar in a container chosen by you and then position it as you wish. Check the second demo (Inline Editor with Shared Toolbar and Bottom Bar) on the SDK sample page for an example.