To disable Back in Stock Product Alerts button for an individual product you can hide the button on that product. 

Goto Shopify Admin Console > Products > All Products > Click on the product to edit > Tags > <Create your own tag name> or use our default tag <swym-disabled>.

Now go to Swym Dashboard > BiS Product Alerts > Disable on selected products > Enable 

Enter the tags of the products that you want to hide the button on. Example: You have 10 products that you have tagged with “swym-disabled” and do not want our Back in Stock Product Alerts button to show up on them. You can just enter “swym-disabled” in Add tag section“, and the button will not show up on those product pages that have been tagged.