This is truly an (accidental?) setback of color reproduction as it has progressed over time. For LED lights R9 is also crucial for skin tones which makes it so bad to just leave that out. Now, the mass produced LEDs are even optimized for CRI at all are virtually all excluding R9, which may be one of the main quality issues that many people perceive with LEDs vs eg incandescent. There’s of course more to it but R9 probably has a disproportionate effect for being a ”minor detail”.