Eight is a good age to learn to read.

Age is irrelevant.

The important thing is that he wants to learn.

And that he be developmentally ready. Willingness can come before the areas of the brain involved in reading develop enough for reading to be possible.

Some people object to phonics because it seems like just a lot of rules without practice in actual reading.

That objection would apply to someone who is looking for a process to move the child from where he is to where the adult wants him to be. Since that isn't what motivates unschoolers, it isn't what they'd object to.

Unschoolers would object to doing anything with a child that the child has no interest in doing.

Unless he learns phonics, he won't be truly reading. He'll be memorizing words because of their shapes. Phonics is, simply, the skill of changing letters into sounds.

Phonics will come naturally with reading. We're hardwired to pull out patterns from chaos. We need to find patterns. Have you ever found yourself staring at something, trying to figure out what it was? That's the drive to find patterns kicking in.

Some kids do like rules -- rules for anything -- given out explicitly. Some kids don't. Your son will let you know what he needs. If he's asking you to read the instructions before he starts something or does find the cat, bat, hat, mat combinations fascinating, then he'll probably like more of the same type of game.

Short i....bib, bid, big, bin, dig, pig, rip, hit, nip, did

Short o...bob, bog, bot, or cob, cod, cog, con, cop, sop, pop, hop, top

If the child is fascinated by these patterns, then it would be fun for him. But it's very difficult to read words out of context. It's especially difficult if the child has no interest in reading them and doesn't feel the reason for doing so is worth the doing.

There's a good book called Hey! I'm Reading! A How-To-Read Book For Beginners by Betty Miles. It's for both parents and beginning readers about how we read and the strategies we use in reading.

Here's part of the review at Amazon:

By telling young readers some things they already know (that letters are part of writing, they know how to talk -- talking is good practice for reading, they know about books, and they know about many of the things they will read about -- dogs, cats, the moon, stars, tying shoes, zipping zippers ...), Miles encourages kids to take the next steps. She suggests that beginning readers learn to read by getting help from pictures, remembering words, sounding out letters, expecting what comes next, writing words themselves, and trying to figure out if what they're reading makes sense.

The book might help your son when he's in an "I want to learn to read" phase.

It's necessary to see long words as being made up of short parts (consonants) that he can read by themselves, and put together in his mind as longer words. If he does that, he is learning how the English language works.

While it's helpful for a reader to be able to do that, it isn't necessary to teach it. That skill will develop naturally along with reading. We need to balance on two legs in order to walk, but no one needs to teach a child to balance before they walk.