Lying is a great thing!!!!!!I know that sounds crazy....but lying is a "typical" behavior for "typically" developing kids! 8 years old is on mark for children to try and test the waters and get away with something they did and lie about it. You can be a little happy about it. A little lie here and there is part of growing up. Congrats
I'm big with social stories with my child. Maybe you could try one?
You can't put up links on this site, but if you use "social stories" for your search I'm sure you could find one or get some ideas on how to write one for him. Hope this helps. Good Luck!!!