Do you really mean IE9? (Is this on Windows 10? What is the default browser on the devices in question? Edge?)
Isn't IE being deprecated very soon. June 15, 2022
https://learn.microsoft.com/en-us/lifecycle/announcements/internet-explorer-11-end-of-support
Therefore you need a plan for any apps that only work on IE.
If it wasn't for the fact that IE is going I would have recommended Edge Internet Explorer Mode (EMIE).
https://learn.microsoft.com/en-us/deployedge/edge-ie-mode
You need to maintain the list, but you can force certain website to open in IE should compatibility be an issue.
Otherwise just set Chrome as the default browser.
Although why not Edge, they are both Chromium based.
Or are you saying that some sites won't display properly in Chrome\Edge? (Even more need for a plan for those sites).