Answer: If you use a vegetation killer such as glyphosate (Round-Up), there is a waiting period, but I think one-year is excessive. From what I am reading on the label, the recommendation is to wait 7-10 days after application before planting in the area. If you choose to use an herbicide, be sure to read and follow the label directions, and be careful of overspray or drift - this product will kill on contact.
As for reseeding the area, you might want to choose a shade-loving grass variety, or one that is labeled shade/sun mixture.
Best wishes with your project!
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