Can you wipe a MacBook pro's ssd if it doesn't have a firmware password?
Sorry, you're out of luck. If they boot into recovery mode, they can wipe the drive without going online. Even if they went online, your iCloud information is stored on the encrypted, unmounted drive so the recovery OS isn't going to log in to your account and report the location anyway. Report the theft to Apple in case the thief, or a buyer, goes to an apple store for help with your machine.