As a lawyer, I assume you understand better than most the dynamic between adults and minors and the reasons why ages of consent, and ages to choose things for themselves, are in place versus custodial rights (and psychological influence, power, etc.) you have.
That said, I do think 8 or 9 year old's can choose good things to rally around and be in support of, such as BLM protests, etc. My children wanted to participate after we showed them the George Floyd video. It was heartbreaking to see my youngest be really effected--and scared. I questioned was I being a good parent by showing such a young kid and giving them access to the reality-- or should I be doing more to shelter/shield them. I ultimately think I landed on the right thing, for us, but I don't judge anyone who doesn't want their kids to know about the wickedness and brokenness of the world.
But the question remains, are the 8 or 9 year olds acting off of some pure, primal sense of justice and what's right, existing since time immemorial? Or are they influenced by the parents? It's also the constitutional right of an 8 or 9 year old and his parents to go to a Klan rally or Unite the Right rally (perhaps, same difference?), but isn't that using children as political puppetry and/or an example of children being influenced by their parents?