Oh how the times have changed... Zatch Bell was my #1 favorite anime for a long time while I was in middle school and it was airing on Cartoon Network xD I supposed there's the "appropriate for home watching, but potentially not at school" aspect, but still.
On topic, racking my brain and going through a big ol' list...
Angelic Layer might be okay and was pretty good. Been a few years since i watched it but I remember it containing mild violence between toys/robots and can't recall sexual themes.
Prince of Tennis was another that I liked a lot around that age (and actually inspired me to learn how to play a little bit and join the school team in high school)- This one should be 100% fine as it's just a cut and dry sport anime lol
Bakuman's a lot of fun (as a comic artist xD) but not much of it is dubbed, I watched it subbed
MAR is another that I really liked around that age, mild fan service but may or may not be over the allowable threshold lol.
Megaman NT Warrior- loved this game series, and loved the show too
Sonic X- see above
The Melancholy of Haruhi Suzumiya - I don't thiiiiink this has too many sexual jokes? Another that it's been a good number of years since I've seen it though and can't remember