Update to python 3.9. #60

Job	Run time
pylint	16s
pre-commit	11s
test_on_EOL_Pythons (2.7)	20s
test_on_EOL_Pythons (3.5)	23s
test_on_EOL_Pythons (3.8)	4m 39s
test_on_EOL_Pythons (3.6)	5m 42s
test_on_EOL_Pythons (3.7)	5m 27s
test_on_supported_Pythons (3.9, ubuntu-24.04)	4m 9s
test_on_supported_Pythons (3.11, ubuntu-24.04)	3m 14s
test_on_supported_Pythons (3.9, windows-latest)	4m 1s
test_on_supported_Pythons (3.9, macos-latest)	3m 38s
test_on_supported_Pythons (3.10, macos-latest)	3m 9s
test_on_supported_Pythons (3.10, windows-latest)	4m 30s
test_on_supported_Pythons (3.11, macos-latest)	2m 9s
test_on_supported_Pythons (3.10, ubuntu-24.04)	4m 4s
test_on_supported_Pythons (3.11, windows-latest)	3m 58s
test_on_supported_Pythons (3.13, ubuntu-24.04)	3m 17s
test_on_supported_Pythons (3.12, ubuntu-24.04)	4m 0s
test_on_supported_Pythons (3.12, macos-latest)	2m 25s
test_on_supported_Pythons (3.14.0-beta.4, windows-latest)	5m 34s
test_on_supported_Pythons (3.14.0-beta.4, ubuntu-24.04)	3m 52s
test_on_supported_Pythons (3.13, macos-latest)	2m 27s
test_on_supported_Pythons (3.13, windows-latest)	3m 42s
test_on_supported_Pythons (3.14.0-beta.4, macos-latest)	3m 12s
test_on_supported_Pythons (3.12, windows-latest)	4m 9s
	1h 22m 28s

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