Christina, I can create a packing list with a barcode that represents the order number. My invoice/packing list widget works with Shopify Order Printer which is a free app from Shopify. You set up a new template for your custom packing list, name it and save it. The select Shopify order Printer to pring your barcoded packing lists.
Making the scan send you to your order is a more complicated request. I developed an app that does what you want and a lot more. It currently requires a ShipStation or eHub account (both Rate-Shipping companies).
I will be launching my app, Scan2Ship live next week. In the meanwhile, if you want me to create code you can use for a barcoded packing list, I would be happy to do that for you for free. Just let me know.
Here is the promo for my app:
https://youtu.be/oGTIqlXOAD0
My Shopify ecommerce site where we have used Scan2Ship for years:
https://www.lillarose.com/
John Dorsey