chore: Investigate upgrading the library to AGP 9

[TheRealAgentK]

Please describe your new feature request
Currently AGP 8.13.2 is still ok and can be used against Gradle 9. It's only a question of time though before AGP 9 will become mandatory and Gradle 10 is already on the horizon with its own deprecations.

Describe the solution you'd like
Full and complete upgrade, upgrading all then deprecated and broken functionality.

Describe alternatives you've considered
There is none

Additional context
Will need to be slotted into other work, needs internal prio.

[TheRealAgentK]

Related to #254