It's impossible to combine a book with scorching heat on it with any tool in survival. It's also impossible to add it to any tool with the Stellar Refraction Table.

Idk if this somehow helps but while yawing the valhelsia 3 mod, that has astral sorcery in it, I was able to actually enchant a pic with scorching heat. It stayed with me and continued to work through 3-4 updates of the mod. I took it off recently so I could try and get more of the enchantment since it couldn't be found anywhere else via trade, soul enchanter, or regular vanilla enchant table. After I took it off it could no longer be applied to any tool. I also have reason to believe that in one of the updates it turned any already existing scorching heat enchant books and turned them into blank white enchant books