" I am talking about working on a Word document..."
Are you working in MS Word then? If you were working in Pages, you would have been working on a Pages document. Pages can import Word documents and can Export a Pages document to a Word format file. Importing includes translating the Word document from its native format into a Pages document. Exporting includes translating a Pages document to MS Word format before saving it.
The question is about removing the highlight colour in Pages. cntrl+spacebar may remove colour highlighting from the text background in MS Word, but it did not do that in my tests with Pages 4 and Pages 5, as described in the screen shot of my test document below:

You are correct in stating that control-spacebar does not open Spotlight.
The keystroke combination to open Spotlight is command-spacebar.
You err in 'thinking' the most-updated version of Pages is 9.
The current version of Pages is 6.x.x
You can find the version of any Apple application in the first item of the Application menu when that application is running. When Pages is the active application the menu is named Pages, and its first item is About Pages.
Regards,
Barry