Reddit mentions of TIME For Kids Big Book of Science Experiments: A step-by-step guide

What sort of science book are you thinking? Animals, space, DIY science experiments?

Here's a great general science book from National Geographic: http://www.amazon.com/National-Geographic-Kids-Why-Everything/dp/1426320965/ They also have a great animal encyclopedia and a "weird but true" series that would definitely appeal to a 9-year-old boy :)

For science experiments, you could try http://www.amazon.com/Great-Science-Experiments-Neil-Ardley/dp/1465428267/ or http://www.amazon.com/TIME-Science-Experiments-step-step/dp/1603208933/

Also, this is probably way more info than you want, but here's the annual recommendations of the National Science Teachers Association: http://www.nsta.org/publications/ostb/