I just purchased a Model Nine Signature last week for $1,350. According to the Ultimate Audio Review (link on Muse's website) this was a significant upgrade to the Nine. My advice would be to sell the Nine and upgrade to the Signature. There was one for sale yesterday. I would think the price differential would be $300 to $500 after selling your unit.
For the extra $1,800 it doesn't seem to make sense to upgrade to the Ten. You can buy a lot of CDs with $1,800.(My prinary interest is vinyl.) Very likely the 11 Upgrade will be $3,000 to $4,000.
For SACD, I will probably purchase the Sony SCD-3000 XA from England for about a $1,000. Unfortunately Sony does not sell this wonderful SACD player in the US, only the 9000 model which is 2X to 3X as much. The 3000 was rated 95 for SACD Sound by a British Magazine. Again for the money differential you can buy a lot of SACDs.