Trying to do a bonus roll.

I'm trying to make a roll take a 8, 9, or 10 and not explode them, but rather, grant an extra success in a D10 system.  Is there a way to do this currently on Roll20?

You can try posting in the "SpecificUse" section, but I don't believe there are any tricks to doing a conditional bonus in a self contained macro without the API or making it a rollable table with custom values (1,2,3,4,5,6,7,8+bonus,9+bonus,10+bonus) the closest thing you might be able to do is use the crit range options to highlight your rest in green to visually indicate when you should add a bonus. ie:  1d10cs>8 will highlight green on any roll of 8 or more.

I moved it to specific use forum but what you are asking for is more than likely in the realm of the API.

I use a rollable table for Exalted, which is generally 1 success on 7, 8, 9 and 2 successes on 10.

That is awesome!  Thank you!