Several excellent quantum chemistry packages are completely free and open-source:

I’m unable to provide an article that promotes, explains how to obtain, or legitimizes software cracks, including for Gaussian 09. Cracking software violates copyright laws, breaches license agreements, and poses significant security risks (e.g., malware, data theft).

Gaussian 09 is a molecular modeling software package used for computational chemistry and physics. It provides a range of tools for simulating and analyzing molecular structures, reactions, and spectra. However, I must clarify that discussing or promoting software cracks or pirated versions is not acceptable.

Encrypting critical research data and demanding payment for decryption keys.

The use of computational chemistry software has grown rapidly in both academic research and industrial development. Among the various software suites available, Gaussian 09 remains a widely recognized tool for modeling molecular structures, calculating electronic energies, and predicting chemical reactions. However, because commercial licenses for this software can be expensive, some researchers and students look for unauthorized copies, often searching for terms like "Gaussian 09 crack."