When choosing, you need to consider and understand the following points. The store does not sell BGA kits for working with eMMC, they are purchased separately on Aliexpress and similar sites.
Which of the Chinese BGA kits to choose and buy depends only on your preferences, finances and what is being sold there at the moment. The UFPI store only sells adapters for these "standard" Chinese kits. Those. the question of choosing an adapter to work with BGA eMMC comes down only to what set of BGAs you will have or already have. There is a printed circuit board for the RT809 programmer that will allow you to independently assemble an eMMC socket for UFPI and use the existing BGA adapters. If you have or plan to buy, for example, an EASY JTAG EMMC BGA kit, then you need to buy a UFPI EASY JTAG eMMC socket, etc. If you need to work only in ISP mode, then it makes no difference which eMMC adapter you need, all will do. If you wish, you can assemble the adapter yourself, the adapter diagrams are in the appendix to the User's Manual, clause 16.3 and on the manufacturer's website.