The nine-year-old (NOW 10-YEAR-OLD!) recommended this to me. I read it during the eclipse. I'd read a little, run outside, look at the sun, run back inside and repeat.
I can see why she likes it. It's very easy to read, but there's some intrigue and some family drama. I found Sunny's relationship with her grandfather the most interesting part of the book. If the sequel focuses on the two of them, I might check it out.