Why reinvent the wheel?
The honest truth - no one actually reads the rating scale for each site. The 1-10 scale is ingrained in our psyches. If your 6 correlates to everyone else's 10, everyone is going to assume you thought the game was a 6 out of 10, which generally means "meh".
Either go with 1-100, 1-10, 1-5 or A-F. Theres no need to confuse people with a 6 or 9 point system just to be original.
Considering your writing for a university newspaper, and that its a scheme that anyone can naturally understand without having to consult a scale, I recommend A-F.
A- Excellent
B- Good
C- Passable
D- Scraping By
F- Fail
Theres virtually no other interpretation for those letters, unlike the 1-10 scales where 5 is "average", yet average review scores usually hover around 6-7.
Whether or not someone is going to buy new, buy used, rent etc has more to do with how much money they have, or how hardcore they are - leave that up to them.