Correct the name of the Airfow v2.9.0 folder + Minor changes + Update README.md file

[rafidka]

Issue #, if available:

N/A

Description of changes:

• Correct the name of the Airflow v2.9.0 folder. (it was called 2.8.0 even though it is actually 2.9.0)
• Other minor changes.
• Update README.md file.

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