Our 9 and 11 year olds love the Week Jr. We have even started to let them respond to the various polls. I think the magazine has really broadened their understanding of the world and current events, which was needed since we don't ever have the TV or news on.
We also get the Washington Post on Sundays and let the kids read that, though mostly my 9 year old is just in it for the comics at this point.
Children’s section at the library should have a variety of kids magazines for your kid to peruse and tell you what they like. I thought DD would love Cricket, but she would never pick it up. She LOVES The Week Jr.
Definitely check out the library's offerings to see different options. I heard so much about various kid's magazines, but when I looked in person, so many of them made my head swim with how "busy" they were.
My kids get both and they prefer The Week Junior. I think 4th is probably the latest for Nat Geo Junior - my 10 year old will still read it, but my 12 year old has aged out of it, she has no interest but both kids really enjoy The Week.