MB Synge 9th grade?

Hi, has anyone used MB Synge  (Struggle for Sea Power) for early high school? I will do AO9, but the recommended Churchill’s book is too detailed with politics and battles, without more of the world represented.  But I do not want too easy of a book for her.  She will do a US history “spine” in conjunction. I just want an engaging book on world history for her from 1688-1815.