Point the shopify "buy button" to the shopify "cart" page instead of the "checkout" page

[imcdigital]

I'm looking to point the shopify "buy button" to the shopify "cart" page instead of the "checkout" page from our website so that our customers can select a preferred ship date, is this possible to add a script to accomplish this? 

Or if there's a way to add the select ship date on the checkout page of shopify or within the buy now button that would be awesome too. I was able to add the ship date selection snipet to the cart page, but not the checkout page.