I can't quite follow whether you're talking about actual Critical Race Theory, or what the word has come to mean to both the left and right.

If you mean original Critical Race Theory, it's worth noting that although it began as a legal theory (initially more in the scientifically-aspirational Legal Realism vein, but it hopped teams to a more Critical Legal Studies approach, in the vein of Critical Theory), its philosophical/activist roots have never limited its aspirations to law alone. A good brief resource is Delgado & Stefancic, Critical Race Theory: An Introduction, 3rd ed, (2017). One of the chapters near the end (~page 160) goes into detail about how CRT, at least in the authors' views, could be reflected in wider society.

It's certainly not originally about teaching history. Indeed, the narrative approach favored by CRT is antithetical to the ideals of history as a social science, which is to say that although all perspectives are biased, one strives to nonetheless to hew as close to an unbiased truth as possible. This involves considering context and importance of events, not just cherry-picking events to aid your narrative vision.

That CRT was about teaching kids history was essentially left-wing misinformation (somehow non-ironically said at the same time as the also-misinformation that CRT was only a grad school legal theory and never taught in schools). The left came up with it to counter right-wing misinformation that CRT was about discriminating against white people (and was everywhere in schools--more misinformation).

To complete the circle of absurdity, the right wing is now banning the teaching of history because CRT=bad and the left says teaching history is CRT. It would be comical if it were not so tragic.

Furthermore, if you look at a CRT-inspired ethnic studies curriculum, you do not find the material to be obviously age-appropriate, meaning that the concerns about the attempt sending the wrong message are potentially valid and should be examined seriously instead of being dismissed presumptively as arising from adult shame and guilt: https://www.oregon.gov/ode/educator-resources/standards/socialsciences/Documents/Ethnic%20Studies%20Webpage%20Communication.pdf.

Not sure about you, but even the bright 3rd graders I know might find it hard to "Understand and analyze the impact of systems of power, including white supremacy, institutional racism, racial hierarchy, and oppression."

Anyway, if by "teach kids CRT" you mean "teach kids the history of slavery along with the rest of United States history", yes, they can handle that, have been handling that for decades (in some states more than others), and the backsliding on the right on this is horrid.

If by "teach kids CRT" you mean "teach elementary school kids the ideas of presumed competence and ordinariness of racism and expect them not to conclude that white kids are guilty and evil and they have to obey non-white kids", well, good luck with that.