Since the hole is above the waterline I'd apply the patch, using Boxer-100, then use duct tape to hold the patch in place for a few days until it bonds. After a few days pull off the duct tape and you may be able to use isopropyl alcohol to remove any duct tape goo. Guessing at this. Boxer-100 is a slow acting adhesive that won't aggressively attack the patch and curl it, but, it takes some time to bond. I was the one last year that started the suggestion about Boxer. Researched a lot of adhesives when I had a deep end slit in my liner and found this stuff worked just fine. Other vinyl cements are agressive and curl the heck out of a patch before you can apply it.
Al