The WRAML-2 is a good comprehensive memory test that is applicable to his age group. There's also the WMS-IV, but you have to be at least 16. I'm assuming he's not. Odd that your tester should say the CMS doesn't reach his age range, as it goes up to age 16 (the WMS and CMS are sister products--or at least marketed as such). It does have two forms, for different age groups. Perhaps he/she doesn't have the forms for ages 9-16.
Yes, I would not be surprised if he adapts, and figures out his own strategies for organizing and monitoring assignments and directions. He clearly has well-considered ideas about what will work for him, and is not afraid to advocate for them. I like his #3 idea quite a bit, although I agree that it may be difficult to implement.
