we're just going to reply to this 8 years later in case anyone else comes here. yes, twenty one pilots is appropriate for a 9 year old. their main audience might be a bit older (14-17), but they're definitely family friendly. there's no swearing, other than "hell" a few times (refering to heaven and hell) and "whore" in ode to sleep (a biblical reference. see judges 2:17). their music talks a lot about mental health and i'd be deeply concerned if a 9 year old related to those dark topics, but it's still enjoyed by any age. the deeper meanings are dark, but their music is still open for interpretation and good for any audience. it's saved lives. they saved mine. but a 9 year old should NOT be exposed to something like a fifth harmony concert. sure, the music might be catchy, but that is not appropriate for a child in any way, shape, or form. twenty one pilots would be a much better option.