If it is legal for schools to keep a cell phone for 9 weeks would depend upon what their code of conduct rules say. Most schools will not keep a phone for this long.
No, it isn't legal to bug cell phones or jam them.
No
no
my high school
No
It is legal to use on your kid or employee or on a phone you own
Yes, that is perfectly legal.
yes
Yes.
If you are the legal owner, you can get copies of call logs and locations where calls were made from the cell phone service provider.
Laws vary from area to area, but in general, it is legal to law enforcement officers to search a cell phone if it is believed that the cell phone contains information pertaining to the arrest. To give a specific answer, the geographic area will need to be provided.
yes