Yes, I have sprayed some areas with roundup and planted there. It works good on many things. However, one thing to keep in mind. If you are planting this fall, it is too late to kill all the plants growing there now. Most of those plants have already gone to seed and many may even be done growing this year. If you spray now, you will probably have a lot of stuff coming up there next year again. The best way to get a lot of the area freed up for sang is to keep it sprayed and clear for the whole summer. That way you get the plant as it is growing and the chemical gets to the root system killing the entire plant.
Another thing, you mentioned invasive species. Some things roundup will not kill. Usually the woody grain type plants may need something made for that type of plant and some of those things will have an effect for a time after they are sprayed. Check the labels of whatever you are using.
