How do I reinstall Adobe Acrobat Pro 9 from an old computer to a new one without the disk

Adobe doesn't offer old installers any longer. If you don't find the installer try contacting Adobe Support directly and asking for it.

We here at the forums can't help you with this issue, unfortunately.

you'll need a compatible os (ie, old) and it's no longer secure.  that said, if you purchased from and registered with adobe, check https://helpx.adobe.com/in/download-install/kb/downloaded-older-app.html  for info on how to download non-current adobe programs.

once you download, if you're having trouble finding your file(s), https://helpx.adobe.com/x-productkb/global/find-downloaded-file-app.html

if that fails AND you've (a) registered your software with adobe or (b) can provide proof of purchase, using a browser that allows popups and cookies, contact adobe support during pst business hours by clicking here and, when available, click 'chat', https://helpx.adobe.com/contact.html

for more info on adobe's 5/2019 policy on downloads, https://prodesigntools.com/adobe-limits-software-downloads.html