Can I download and run an earlier version of iTunes on my iPad gen9

Again, iTunes does not control your music on the iPad. The Music app is where your music is housed on the iPad. I think there is an issue with your understanding of the handling of music on the iPad. My guess is this Tempo SloMo is some type of app, is that correct? If you check this app, does it support the later versions of iOS and iPadOS? You may need to check with the app developer. As far as downloading new music on your iPad, that would be done through a purchase in iTunes on the iPad. You cannot download music from other sources directly to the Music app. Music has to be downloaded either from a purchase in iTunes, or you would download music from your Mac, either using iTunes or Finder, depending on the version of Mac OS you have.

The only thing that iTunes does on the iPad is to allow you to search and purchase music, video and movies. iTunes is an integral part of iPadOS and you cannot separate it from iPadOS. What is it that you are trying to do that you want to have an earlier version of iTunes?