An indication of the price that you're willing to pay might help here.
I've had some recent experience of buying presents for that age group (for my lad's son, who's now 11, and for my friend's son, who's now 12) but not for girls. However some of the presents I've bought over the past few years might still be suitable.
Firstly, anything personalised with the child's name on it seems to go down well. For example, my friend's son (who has two ragdoll cats) loved the T-shirt I designed for his 11th birthday:
https://ibb.co/jz2pgKG
Science and technology kits seem to go down well too. I've bought these over the past few years:
https://www.amazon.co.uk/gp/product/B08B1TT2V8
https://www.amazon.co.uk/gp/product/B00GNJRR76
https://www.amazon.co.uk/gp/product/B07MCCCD8V
https://www.amazon.co.uk/gp/product/B00MNI6XD0
and anything in the Horrible Science range is likely to be a hit with any child:
https://www.amazon.co.uk/s?k=horrible+science&ref=nb_sb_noss_1
I always include books among the presents I buy for kids. These might be worth considering:
https://www.waterstones.com/booklist/1708061/the-best-paperbacks-of-2021-for-9-12-year-olds