We bought this for our 2 month old, and he was almost too big for it.  He's 50th percentile in height/weight, so I'm fairly certain most 9 month olds would not fit in it.  The materials are cheap, but that was expected.  The "peas" on the costume were a little smaller than the picture which in my opinion makes the item not quite as cute.  Definitely do not purchase this for a child much older than 3 months!