For now, the plugin has no direct option to exclude the Sundays but you can block the particular dates by adding it to “Datepicker/Weekpicker: Block Dates” this option from WooCommerce > Settings > Booster > Cart & Checkout > Checkout Custom Fields settings. You need to add a single date in each line.
Thanks for reaching out to us. Yes, you can add whole numbers as well as a decimal number. Also, you can set the minimum, maximum, and default price from the product edit page. Let us know if you have any further queries. We are here to help you!!