I think you have enough if you load it with the 89" on the rollers. 1 inch extra on the sides should be enough. It will be close but doable. It will make you keep the sides really straight.

Add to the sides, rather be safe than sorry.

By chance when you square the quilt up after quilting it, do you plan on cutting off maybe an inch all the way around it. If so, you probably will have enough.

The results...
 

So, this is how it turned out... When I went to load the quilt, the batting was a tiny bit bigger than what it originally measured out at. I had already added a piece down one side as you can see so loaded it with skimpy margins on both sides. I’ve travelled the length of the quilt now, ditching it so I can take it off if I don’t get it completely quilted before I need the machine before Christmas projects are ready. I left the extra strip on, attached with iron on Pellon on the backside, just in case. I don’t need it for the quilt, but it has provided a place to test my tension. I’ll include a couple pics of what I’m quilting on it. Thanks for all of your responses!!!

having upload issues... pics will follow :(

So here are the pics!