Gagging and throwing up is normal. You're asking him to learn to eat in a way that thus far has been completely foreign to him. And he has to learn to do it and that takes time. Just like when he learns to walk, he'll fall down until he gets the hang of it, when he learns to eat real food, he'll gag and be sick a bit to start. This is particularly difficult when you've started on purees and are now making the switch to finger foods. We did BLW from 6 months and there was a bit of gagging for the first 2 weeks, but I think the transition was much easier as she hadn't been used to or expecting purees. One piece of advice would be to not break things up into small pieces. Give him a whole biscuit or a whole piece of banana (we always cut the banana into thirds so she has sticks of it that are roughly 3 inches long) or a whole mini rice cake or roasted carrot stick or whole steamed broccoli floret. It's much easier for them to eat finger food when it isn't so small they have to put the whole thing in their mouth right away. If you leave it big, he can hold it in his hand and suck on it and bite off pieces that will be manageable for him to eat. But really, it just takes time and you have to be patient and trust him to do it. I assure you, he can though. We did BLW, so only finger foods from the start and never a single puree. My daughter was eating pieces of toast, and those bananas cut into thirds, and whole rice cakes, and cucumber sticks, etc. from 6 months (and with no teeth).