My 9 year old won't stop talking and behaving dirty.?

My 9 year old daughter always has talked about farts and pooh but I've heard that's just a thing that comes along, so I just usually tell her it's disgusting, and it's normal to 'fart' then just ignore her. But lately she's been talking about - '' plus she always wants to hump mummy and daddy (especially daddy) - She's only 9! Also if we go out in public she'll yell out silly things like ' Mummy and daddy had ' then she'll laugh her head off. It's very frustrating an embarring , I'm not sure how to correct this , Is she old enought to head the talk ? I was going to wait till year 6 when they start talking about it. So yeah :( help- Please:! I also have heard word's from her's best friend's mum .. D: