It depends of the players that you play, it always define your expirience of the game, I recomended that you play with your Son, and some cousins more or less of his age, they will be more comprensive and you must control all the situations that wiil appear, greettings.

You could try some of the home brew senerios and customs others have come up with on this site or www.afewmaneuvers.com 

You could also create your own ships out of anything you have laying around. Like a crazy station with a 360° fire arc and strong shields that you have to take out. Just add some numbers to paper and use a salt shaker for a model. The great thing about this game is it is easy to create things to play with and there is no board, just play anywhere.

Just my two cents. 

Welcome!  Definately suitable for an 8yo gamer.  If you can find them cheap (under$30) I would suggest 2 core sets and then add a x-wing expansion and tie advanced.  About $80-90 total depending on where you buy.  In our group we have youngsters up to late 40s all playing together.

Enjoy!

My primary opponent is my seven year old. I started playing “wargames” with him when he was about four and this game is pretty easy to pickup. Multiple core sets is the way to go as it gets you the most bank for your buck but you will need one of each of the expansions just for the unique cards and pilots. The vehicles are fragile but I have to admit I've broken and repaired more ships then he has. Scenarios are fun but you need to judge your child's comprehension of objective driven rules. Some concepts may take awhile but kids pick this stuff up so easily. Rebel builds he can handle quite well but large Imperial swarms cause him problems to play. Its both a proud moment, and sad, when your kid takes you to school.

A couple of Core Sets is a good deal if you wanted the quantities of ships anyway (2 X-Wings and 4 TIEs total). It's also handy to have the extra set of (specialized) dice and another set of templates lying around. It's also cheaper than buying 1 Core Set an X-Wing expansion, and three TIE expansions. 

If you'd rather field the Wave 2 stuff (Falcon, Slave I, TIE Interceptor, A-Wing), over the X-Wings or TIEs, then I'd suggest one Core Set instead. 

Really, any of the ships are viable in the game, so in my opinion it comes down to what models you want to push around on the table more than anything. If you want to push around X-Wings and TIEs, then yes, get 2 Cores. If you'd rather push around other stuff, buy 1 Core and the other stuff. 

As for an 8-year-old playing, I think it's quite do-able. Worst case scenario, you can always adapt a more simpler "lite" version if he doesn't get his head around it. 

Have fun!