First, always great to see someone else getting their kids into SR! I’d introduced my son to a different game, but when he found my old 2nd edition SR books he immediately asked if we could switch to ShadowRun.
And now a couple of extra documents you should be aware of, beyond the Core Rule Book (CRB). Be aware that the first printing of the 6th CRB had a lot of editing lapses. There was ~4 pages of ‘hot fix errata’ released when the book came out, and a more extensive errata document is supposed to be coming out within the month. If you get the pdf it has the hot fix errata included already, and hopefully will get updated with future errata releases (but no promises). If you decide to buy the hard copy book, do make sure to get the errata document.
Also, Missions generally have some Missions specific guidelines and rules (for example, some negative qualities just can’t be dealt with properly in the context of one shot missions and may not be allowed). I don’t recall that document coming out for 6th edition yet, but it would be something to keep an eye out for if you want to start building characters before the workshop.
Have fun!