[Zeke]

I'd keep the wall as tight to the higher ground as possible. Putting a planter, e.g., a softer soil, against the high ground will make things worse, IMO. If you want a planter, do a double row of your intended construction and use braces or kickers along the outer wall that won't be seen when you backfill the planter. This way you can use less of a footing and less strength along the outer wall. The inner wall only needs to be strong enough to hold the soil. I would also step the planter fill down about 1/3 of the total height at the highest point and keep level as far as it makes sense.