Ask your Pediatrician or Lactation Consultant....
All I know is, that for the first year of life, a baby's PRIMARY source of nutrition is breastmilk/formula. So, this still is an important part of their diet... and for just preventing dehydration if anything.
Is she drinking anything else? Do you give solids before or after breast? Usually, if giving solids BEFORE breast... this makes them too full to nurse after. Usually, giving solids before breast/nursing is done to "wean." So usually, the recommendation is to nurse first BEFORE solids....
Maybe she's teething? Or is she sick or anything? Sometimes this affects their nursing....
Just make sure she is getting adequate intake.... or perhaps she is just changing.. .and instead of nursing as frequent... she is nursing less often but for longer periods and more per sitting???? Sometimes, once they are this age and on solids...their frequency of nursing will seem to lessen... but their intake is more per sitting...
I would ask the Pediatrician how much quantity she should be drinking for her age, and per her growth percentiles etc....
I would not assume she is "weaning" just yet... until you rule out anything else, or ask the Pediatrician about intake quantity for her age....
Both my kids self-weaned... but they were older than 9 months. My daughter being 2.5 years old, and my son about 1 yr. old when he self-weaned from breast and then he just preferred the bottle because it's easier to suck on....
Is her poop/pee diapers normal? Watch for dehydration... and don't only fill her up with water.... breast/formula still plays an important part of their diet and for nutrition sake...
All the best,
Susan