What type of plan is this—a 457? If your total fees are actually 0.9%, then use the plan.  The fees plus the ER of the index funds (assuming the ER's are very low) puts the total costs on the low side on most plans.You should probably fund both the DC plan and a Roth. If you can't add 10k to Roths and fund the plan, then maybe add 5k to a Roth and fund the plan with additional money.

You haven't provided your age, but if you are 30 for example and contribute a total of 10k per year for 30 years, you will end up with about 1.4 million in today's dollars (not inflation adjusted). That will allow a safe withdrawal rate of $56,000/year.

Paul