Remove python3.9 support & ensure tutorial tests only run when required

[edwardchalstrey1]

• Closes [Test]: Skip notebook tests locally by default #659
• Also updates the supported python from 3.9-3.13 to 3.10-3.14

See discussion on #661

Can now do pytest --run-tutorials, doing just pytest skips tutorials

• Update --run-tutorials logic so that if pytest tests/test_tutorials.py is run, the tutorials tests are still run, even if --run-tutorials not set
• Update developer docs on running tests locally to explain --run-tutorials flag usage
• Update package metadata to remove 3.9