Does it work with PrestaShop 1.7, 8 and 9?

Yes, PrestaShop Recently Viewed Products Module is intended for PrestaShop 1.7, PrestaShop 8 and PrestaShop 9. It uses PrestaShop placement hooks and a browser cookie to remember products without requiring customer login. After a theme update, check hook registration and review the storefront block so placement still fits your design.