Can you develop a 3D scanner plugin for Octoprint that can import 3D models from 3D scanner directly？
In theory, sure. In practice: not so much.
You could create a plugin that interfaces with the hardware and creates an STL model, then sends that STL model to a slicer and creates gcode, which can then finally be handed over to OctoPrint. But - unless you add that functionality to the plugin too - you will have no way to edit/clean up the mesh, which is almost always necessary after scanning.
So in short: you would be rewriting/replacing all the software that comes with the scanner, which is probably proprietary, so you would be doing that from scratch with no info.
Use tools what they are intended for. OctoPrint is intended to send gcode files to the printer.