The benefit of redshirting is you get a season of extra development, which can be very useful since it means the guy might play most of his junior and senior seasons at A+ IQ. It's also nice for guys who start in the low 20s in PER or LP but have high-high ratings as it gives those a chance to climb nicely while the player still has games left in his career and without you needed to short-sell development in other areas.
The down side is that, with 9, you'll probably be playing slowdown the whole season. Your opponents will likely go uptempo all season and unless you're in a zone defense, you'll probably get stuck on depth/fatigue at some point during the season. The stamina ratings of the other 9 will also be something to give a good look at.
If you're not planning on contending this season, then I'd say go for the redshirt and start planning for the future.