I have found a strut tower brace for an 09 Prius for less than $50! However, I know that there are differences between this unit and the one for my 2010. Can this unit be made to fit or adapted? If so, that would save @ $100.
Almost certainly, no. The 2009 and 2010 bodies are too different in the front. Of course, if you have access to a machine shop and lots of time & money, anything is possible. I've actually never seen a 2009 part offered for a 2010 application. There may be some, but very very few.