lol@ scruffy! Bless!
Bob isn't very big though slightly large than most beardies, was a bit of a stud in his days

not measured him, but nose to base of tail i'd say about 9 or 10 inches at a guess.
Iguanas grow much bigger and mostly become aggressive, usually by tail-whipping you. And you need a large vivarium for when fully grown. I'd say they're only for someone who has a real interest in reptiles and has prior reptile experience.
I would instead get him a bearded dragon as they are most popular, reasonably easy to look after, if handled from babies they are generally docile and do not bite as a rule unless not used to handling, etc.
I once hatched off 96 bearded dragon eggs, bob was the dad and I had 2 females at the time, and which resulted in 73 hatched babies over a period of 2 months. Only one baby died after a few days of birth and one was born disabled and died after a few months on xmas eve

so that was a successful breeding first attempt. It's great to see them slowly hatching from their eggs.
Just make sure you read up fully and do the research, and buy the right equipment and food, etc.