Hi, I have a 9 month old who likes to use a small thin piece of clothing (an old 0.2 TOG sleeping suit) as a security blanket. I am wondering if it is safe to leave this in the cot with her now for naps and at nighttime as she is over 7 month? Cheers,

Red Nose recommends the following.
Keep soft toys out of the sleeping environment for babies under seven months of age because they may cover the nose and mouth and interfere with breathing.
Keep the cot free of large soft toys, pillows, bumpers, activity centres and anything else that could be ‘stacked’ to assist a young child/toddler to climb out of the cot.
https://rednose.org.au/article/can-my-baby-have-a-soft-toy

Also, be careful that the comforter is not too large that it would cover baby’s face