It sounds to me your little guy is right on time with self feeding. It's important to make meals a social occasion. He needs to be eating with you. He'll watch you and Pop eat and try doing the spoon to mouth maneuver. Finger foods are good too. Between, mom's help with alternating spoonfuls, your demonstration of eating, and finger foods, he should do just fine. He'll make friends with food, enjoy family meal time with Mom and Pop (a very important habit to establish when they're very young), and reinforcement of successes.
Don't get too worried about the mess. It's part of learning. One survival trick for mom. When my son (now almost 32 years old) was learning, I spread an old vinyl shower curtain (or use a shower curtain liner-very cheat) under the high chair. After meal time, I'd take it to the back yard and spray it off with the hose.
Let us know how it goes for you and Isaac.