They seem fine to me. I read a number of them in 7-8th grade and
  that was back in ... 1984/1985. Some I read in 6th grade like
  Huck Finn and Tom Sawyer. A few I read in 9th. I'd say it's on
  target.

  I've either read them all, or have a basic familiarity with
  them. Call of the Wild was 7th grade and that book haunted me
  for quite some time.

  I also read "Clan of the Cave Bear" in 7th Grade. I didn't know
  it was a prehistoric romance novel. To me, it was about this
  first human lady and I was fascinated by the different culture
  of the Neadrathals from what I was accustomed to. Thoroughly
  enjoyed it.

  I read the sexy scenes too but since it happened 125000 years
  ago, I figured that was normal for the time and I knew it was
  fiction in any case.

  One teacher was a little scandalized that I read it. She was not
  happy at all. I read it because it looked interesting in the
  public library and you know what? It was.