Amazon CodeWhisperer Free / Individual Tier

There are no restrictions on using Individual (free) Tier to write commercial code as an individual or within organizations.

You are responsible for the code provided by CodeWhisperer as described in the following CodeWhisperer documentation.
So I think it is possible to use that code for commercial use.
https://aws.amazon.com/codewhisperer/faqs/?nc1=h_ls

Just like with your IDE, you own the code that you write, including any code suggestions provided by CodeWhisperer. You are responsible for the code that you write, including the CodeWhisperer suggestions that you accept. Always review the code suggestions before accepting them, and you may need to make edits to ensure that the code does exactly what you intended.