Stephen with around twenty years experience of teaching 8-12 years olds more than any other age group, the one thing I can tell you for sure is go for 'rest-stroke' alternating fingers at first. They find this very acheivable and refer to it as 'walking fingers'. With youngsters this is much better than attempting to teach free stroke at first which will result in frustration, very small sound and difficulty in 'keeping contact' with the guitar.
The other thing is I teach them is solid first position, and keeping the left thumb still. I even stick a piece of foam on the back of their guitar neck to keep their thumb under- they like this, they feel secure then.
They also like chords, and most open chords are acheivable. Some like to use a plectrum to strum - they often get given a 'free' one from the guitar shop. I don't mind them using this for strumming, within a few days they will most likely lose it anyway (ha). Most are happy using the thumb or up and down with finger.
To be honest, they are remarkably receptive to technique and whatever you teach them I am sure will be great!
Classical guitar teacher