The first and second generation Pencil use an entirely different pairing and charging interface.
The second generation Pencil can only be used with iPad models that have the magnetic/inductive dock that is exclusively designed for the Pencil (all current models of iPad Pro, iPad Air5 and iPad mini6). Charging and pairing are performed using the iPad magnetic dock.
The first generation Apple Pencil, compatible with iPad9, uses the physical Lightning port of the Pencil and host iPad for both pairing and charging the first generation Pencil. The first generation Pencil can also be charged using an inline charging adapter and the iPad’s Power Adapter. This pencil can only be used with compatible iPad models that have a Lightning connector; recent models of iPad that feature a USB-C port lack any means by which to pair with a first generation Pencil.
In summary, the Apple Pencil models are not interchangeable - and can only be used with the iPad that has appropriate internal hardware.
Here is the definitive compatibility list for Apple Pencil and iPad:
Apple Pencil compatibility - Apple Support
The three “magnetic spots” to which you make reference are the iPad Smart Connector - used to connect with an Apple Smart Folio Keyboard. This connector has absolutely no relevance to an Apple Pencil.
The physical features (including location the Smart Connector - item #7) of your iPad9 are described and illustrated in the iPad User Guide.
iPad (9th generation) - Apple Support
The iPad User Guide is a rich source of frequently overlooked information about your iPad and iPadOS. The full Guide is available both online using a web browser (such as Safari), or as an Apple Books download:
iPad User Guide - Apple Support
https://books.apple.com/book/id1567104892