Yes, you can use Qt Creator for commercial projects.
From what I've read there are certain restrictions to how you can use Qt with the open source version (due to the nature of the GPL and LGPL licensing). The commercial version allows you to do more things, one of which apparently is to ship modified versions of Qt with your application.
The best thing: None of that matters to you, if you don't use the Qt framework. There are instructions on how to achieve this on the Internet. Basically you select non-Qt Project when creating a new project and then either use CMake as build system or QMake and remove Qt from your builds.
If you do want to use Qt (for for the tools/editor), you'll have to look into what you can and cannot do with the community license.
I know that you're NOT allowed to statically link Qt (must be dynamic) and ship with modified versions of it.
Then there's always the option to make the engine and its tools completely separate entities. Engine doesn't use Qt at all -> You can do what you want. Tools use Qt -> You have to look into the licenses.