I want all words with the same root word to be highlighted on the patent page. Is this possible?

Absolutely!

By default, the keyword highlighter will highlight by character occurrence. To search for words with the same root word, use the asterisk (*) syntax operator in your query.

For example, ABST/*tra* will search for any word that contains "tra". 

This way, keywords containing "tra" anywhere within its spelling are highlighted using the same color on the patent page.