You will not be able to share project between student and comercial version, so getting him an AC9 student version will not help you. Anyhow, AC10 student is free for download, so there is no need to buy AC9.
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Gorazd Rajh
From AC 6.5 onward, Ryzen 9 5900HS, 48 GB RAM, RTX 3080, Win 11