No, it's not possible.
Pre purchasing installs a complete version of the title to your console, and gives you the title key. However, the content doesn't use normal ncch encryption keys -- it uses a special version of crypto called seed crypto introduced with 9.6 -- the encryption key is derived partially from a 128-bit value called the external seed that Nintendo publishes on release date. Numbers that big cannot be brute forced, and so the system is secure -- no playing sun/moon early from the eShop! (If someone dumps a cartridge before release, you'll be all good though).
