I really like this series, I think it's just taken me a bit to get back into it after a break (read 1-7 about a year ago, just read 8 and will read 10 next). Space opera, even though our characters are back on Earth for the most part. The story takes place in a few locations. There are a number of ships, in the air and on the water (ie Vanguard, Immortal, Frog, etc) ... Michael Everheart and others are heading up the Vanguard Islands, there is Outpost Gateway (Roger heading this project), X and others are in Aus-tr-Leah (Australia) searching for the Coral Castle and seeds that will help with the food situation.
Kade is a main character this installment, and there are a lot of flashbacks to earlier in his life. Listening to audio (RC Bray narrating - great job with all the voices and fun pronunciations) while multi-tasking, I'd get a little confused sometimes as I'd start/stop/start the book. Are we in the past, in the present? Some books that are written in two tenses, that can help. This was all 3rd person, past tense. There are/were so many characters though, I had a bit of a hard time keeping track of everyone (might have been easier in e-book, taking notes or utilizing the search function to review).
This was a little bit longer, 500+ pages, but it went quickly. I was getting a little complacent, even amidst all the action ... at times it felt a little like a scene from one of the Jurassic Park movies, where our heroes are about to be eaten by a horrible monster (think raptor) when a bigger and badder dinosaur comes along (mr. T-Rex) and attacks, then something even bigger (Giganotosaurus) comes along ... and our heroes escape while the monsters fight. So many mutated monsters! So many horrible deaths.
At the end, this got super exciting with tons of conflict, all coming to a head. Some may complain of it being a cliff-hanger, this one is certainly the most built-up for the next book I think. Definitely felt the need to continue immediately, and am so glad that I had the audio on hold and ready, and I went ahead and purchased the Kindle copy of 10, as I like to be able to refer to the text (I was able to access e-books for 8 and 9, but in Libby, which is not as user friendly as Kindle, but better than nothing. Just a note, I noticed that books 1-9 should be included in Kindle Unlimited (text). I don't have a current subscription, but just nice to note.)