fetal doppler and everyday use 1st trimester

i been looking for the heartbeat everday in hopes that i will eventually find it im 9 weeks and a bit on the chubby side so i know its harder. I started googling and read that every day use of a dopple can give the baby hearing problems and can interfere with the development of the brain because of the waves it send. ive never heard of a doppler sending waves and i thought the only dangerous thing about a doppler was freaking out if you couldn't find the heartbeat etc. This isnt the case for me i know my baby is ok i just want to listen to the heartbeat being that my first appointment ill be a little over 10 weeks and have been in the dark about whats going on with my baby. Has anyone used a dopplers frequently and had healthy happy babies?