M.,
Is it possible that she is teething? My daughter got very clingy and fussy (for her... still not very fussy, but I could tell) around 9mo when she was getting two teeth in at once. I just comforted her as she needed it and started her on teething tablets. They were recommended by a co-worker of my husband's and they worked great! We give them to her four times a day (three tablets at a time) and they really, really helped with the fussiness and seemed to make her feel much better. The best thing is that she thinks they are some kind of treat and runs over when I get them out and just pops them in her mouth (I've tasted them and they have no taste to speak of, so I'm not sure what the draw is - other than we spend so much time trying to keep her from putting things into her mouth and these are something she's allowed to pick up and pop in her mouth!).
My daughter moved away from wanting to be in my lap all the time after she started feeling better. She had another little bout of "closeness" when her top four teeth decided to all come in together, but once they broke through, that subsided as well. I don't think you will foster any negative behavior if you comfort her through this.
I hope that helps.