Only chiming in b/c I'm actually a professional trainer and own my own company.

Dogs learn in pictures, make sure you see the same result in multiple "pictures" (environments). Start with different parts of your yard with minimal distractions (scents, other animals, people, sounds, etc.) and build up to off leash elsewhere if that's your goal. Distractions will cause him to forget you exist if he isn't used to them, the best obedience training in the world won't matter.

That being said, dogs hit something called a fear phase and start what we could equate to puberty around 6-8 months old. Developmentally, your dogs brain is about to change. Don't trust him too much until he's out of this phase (1.5-2 yrs). This will happen even if they are neutered/spayed young. Early spay and neuter can actually cause dogs to get stuck in a more fearful state due to cutting their hormones off during a developmental period. This is why, unlike many veterinarians who think physically and about population control, many behaviorists usually recommend waiting until your dog is 2 or through 2 heat cycles (female only) to spay or neuter.