How soon can we expect SL-systems available on the API?

Since it’s currently beta and things change a lot, I’m not expecting the static API to have SL-systems yet (e.g. convenants, soulbinds, conduits). For now I’m relying on data mining the beta client but parsing undocumented raw data is not a fun experience.

However, I’m curious what’s a reasonable timeline for these to appear on the API after 9.0? For example, does anyone remember how long it took for BfA’s essences to show up on the API since the launch of 8.2?