Other threads on here have shown that you can run on a lower octane. I have owned 2 MDXs and run mid-grade (89) in both with no issues.
The 2006 Acura MDX runs on premium unleaded (required).
The 2006 Acura TL runs on premium unleaded (required).
The 2006 Acura TSX runs on premium unleaded (required).
No, you don't have to. I use regular fuel in my 2006, and it continues to get a clean checkup every time I take it to a body shop.
Premium Fuel 91 octane.
The 2014 Acura RDX runs on premium unleaded (required).
The 2014 Acura MDX runs on premium unleaded (required).
The 2003 Acura NSX runs on premium unleaded (required).
The 2011 Acura ZDX runs on premium unleaded (required).
The 2012 Acura MDX runs on premium unleaded (required).
The 2008 Acura TSX runs on premium unleaded (recommended).
The 2003 Acura MDX runs on premium unleaded (required).