SRAM describe X9 as “sporting X0 lineage”, and all the parts here bear a remarkable similarity in both appearance and function to the higher-end group. You don’t get any carbon fibre in the groupset, though.
The shifters include useful SRAM technologies such as Zero Loss travel, meaning that the pull lever immediately starts to move the cable with no slop, and 2-Step front shifting, which uses an internal cam to equalise the shifting forces between shifts.
Unlike cheaper groups, X9’s front mech comes in different versions for each seat tube size and cable pull direction, so you’ll need to take care to choose the right one. The upside is a sleeker look, without shims or unused cable guides.
As a less flashy and cheaper version of X0, X9 has a lot to recommend it. It’s only marginally lighter and costs substantially more than its Shimano XT rival, though.