change tests to run on python 3.9 #3301

Job	Run time
test (latest_official, athena) / test	29m 45s
test (latest_official, bigquery) / test	18m 41s
test (latest_official, databricks_catalog) / test	20m 21s
test (1.3.0, postgres) / test	21m 43s
test (latest_official, databricks) / test	13m 39s
test (latest_official, postgres) / test	14m 47s
test (latest_official, redshift) / test	24m 27s
test (latest_official, snowflake) / test	15m 21s
test (latest_official, trino) / test	20m 2s
test (latest_pre, postgres) / test	14m 34s
Notify Slack	0s
	3h 13m 20s

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