Hi roberto,
have build them (jitterentropy-library and jitterentropy-rngd) longer time ago and populated them also in the old forum --> https://forum.ipfire.org/viewtopic.php?t=21276#p118316 for a potential testing and discussion scenario. This topic includes also a link to both binaries but they are not actual. Am build them currently again in actual version which needs some time.
AES-NI has nothing to do with entropy. You are thinking of RDRAND.
And this is already running inside the kernel. It uses exactly the same algorithm and I am not sure if any entropy can be fed to the kernel after the CRNG has been seeded. So I suppose those userspace tools have no effect.