How to choose the version of gcc，kernel and glibc？

Hi，everyone！I want to know the choice of glibc, kernel, gcc version. For example, why does debian 9.4 choose the kernel of 4.9.0.7, gcc is 6.3.0, and glibc is 2.24. What is the relationship between the choices between versions? Can I choose gcc 4.9, glibc 2.0? Or gcc 4.9, glibc 2.1?