If you are feeling a bit uneasy about the verification process for enabling voice chat in Roblox, you are not alone. Roblox Corporation should not require you to blindly scan one of your most important documents and upload it to them just to verify your age. However, since verifying your age is their objective, I figured that is must be OK if I partly mask some of the sensitive information present in a passport typically used for identity theft (such as the social security number). Turns out, it worked.
The last digits of the social security number and the passport document number were simply covered using the adhesive part of a post-it like this:
It still feels a bit overkill for them to require a scan of an identity document, but at least it seems to be OK with them to cover up some sensitive parts.