You can add cereal to the baby foods to thicken them. Also, he might like to hold on to a teething biscuit or graham cracker while you feed him. Seems like both of mine were getting done with baby food and moving to finger foods (canned veggies are pretty squishy) around 7 1/2-8 months, so he might be just itching to get his hands on some food!
We never used 3rd foods. By the time they can have 3rd foods, they can also have squished or chopped versions of what the rest of the family is eating. And, because the 3rd foods are similar consistency to 2nd foods, only with chunks, mine always choked because the chunks would surprise them. For some reason, if I handed them chopped green beans, they knew they had to chew/swallow differently and didn't choke. The 3rd foods would "trick" them into thinking they could just swallow a bite.