Is it safe to use usepackage{fullpage} for book publishing?

I’m putting together a paperback book using the documentclass{book} layout.

I’m starting to use usepackage{fullpage} to get bigger fonts and gain more flexibility in terms of layout.

Final output will be a paperback 6 inches by 9 inches.

Has someone used usepackage{fullpage} and got a paperback approved by KDP (Amazon)? Is it safe? Any issues?