You can easily filter the numbers for voting in the chat by using FrankerFaceZ.

If you don't have FrankerFaceZ yet download it from here: https://www.frankerfacez.com/

Afterwards open up the FrankerFaceZ Control Center and go to Chat -> Filtering -> Block.
Add the following in the "Add a new term" textbox: ^[1-8]$
Change the "Text" option to "Regex".
Make sure "Match Whole Words" and "Remove matching messages from chat" (bin icon) are checked.

Now simply click on "Add" and all numbers from 1 to 8 should not be visible for you inside chat anymore.