They won’t see the packets but will know your on a vpn. Use a hotspot.
I agree with others here - many schools (or other orgs with bandwidth issues) monitor the network because they need to boot off people streaming video so people can actually work. It’s a bummer, but a necessary evil when you don’t have the $$ to increase bandwidth.
Just buy a 4G router or tether off your phone. Hide the SSID to avoid anyone seeing the wifi signal
The good part of using a VPN is that nobody other than you can see what you’re accessing. The only thing the school will be able to see is that you’re using their bandwidth. So long as you don’t stream anything inappropriate, like porn and you get caught, it shouldn’t be a problem. They might pull you in at some point and ask what you’re doing. Or they might just block that VPN from being accessed at your school.
They will see the high data usage against an IP on their network. If you have to authenticate to the wireless using your work credentials then they’re gonna know its your device. If they determine you’re using a VPN to circumnavigate their rules you’re gonna lose your privledges likely.
I’d just hotspot it from your phone instead to the tablet.
By personal do you mean you bought and you own and can take it with you when you leave/quite/retire or get fired?
If the answer is yes, then they can’t see shit if your on a VPN.
Did your job give you the device? Do you have to return when your employment eventually ends?
If the answer to that is yes, then they can see whatever the fuck they want, but they probably won’t care as much as you think. Management tells people they watch that, but the IT department most likely tells management they monitor, but outside of black listed sites, the IT department won’t snitch you out unless you make an enemy.
tl;dr the IT department employees get paid to much to babysit end users unless there is a reoccurring problem.
It depends on what and how their monitoring the WiFi.
They shouldn’t really care about a vpn(I’m a high school student and I use SkyVPN)
Download whatever Netflix shows you want to watch before work and then watch them offline. It’ll save your school’s bandwidth too. I know not all shows are available for download but there are a good amount to choose from.
cell phone service is cheap
If I install my Norton 360 personal VPN
I can’t decide if that phrase makes me want to laugh, cry, or shoot myself.
They can see all unencrypted information going to and from your VPN and possibly some low level encrypted data.
They will know you are using a VPN. As in, they will know you, specifically, are using a VPN. If using a VPN is not allowed, you will very easily be found out.
They won’t know what you were doing on the VPN, however.
If they have keyloggers installed they know everything you ever do. Being their computer and keyloggers so cheap, its a real posibility.
What does “watching WiFi like a hawk” mean? My son’s high school installed virtual machines on all their student computer lab desktops so they could connect to and use chrome book software on the windows desktop machines, so I’m pretty sure the IT department there doesn’t have a good grasp on packet capture or maybe even common sense. 
A VPN is suppose to work for your use case. But I agree with another poster who commented about bandwidth and that most likely that is what they are watching… like hawks.
I don’t like this question at all. It’s the school’s tablet. This should be warning enough to stay away from questionable websites. Sheesh.
If it’s managed via an MDM… EVERYTHING!
Does your personal tablet have any software on it installed by the school IT staff? If not, the chances of them seeing what you are doing is almost zero.
We can see all your DNS request if you allow your unit to grab DHCP first and dont edit the settings and have your VPN set properly. We can decrypt everything if you use our machines on our domain. If you do decided to use your VPN you will become immediately interesting to us and all traffic will be logged and gone over by a human with a fine tooth comb.
That is if you have a competent CISO or equivalent in your company.
They can see what you do on their network. It’s their network. You have to log in to use it. So they can see your activity. Maybe not in real time, but you’re LOGGING IN to use it, there is a record of everything you do on their network.
All you’re doing with the VPN is securing your connection, and changing your IP address. As if you’re using a coffee shop wifi to do school work and are just using a VPN for security.
Can they tell? Definitely. Will they care? Depends on why they are ‘watching it like a hawk’
Have you tried asking the school’s IT staff to unban your tablet’s IP from say, your youtube or Netflix?