Comment 1 for bug 1926477

You can move item and bib records between buckets using pending items. A number of steps but is possible

Select the item or items to be moved.
From the Actions menu, choose Move Selected Items to Pending Items/Move selected records to pending records
Items/records will move to Pending tab
In bucket view, select or create desired bucket.
From Pending, select Move to bucket.

I don't know if the same exists in patron buckets.

I would be nice to streamline into the actions menu, however, since it so many steps.