Based on what you said about water shooting out of the oil filter cap and what it looked like in the video ...
You have a major problem. Water should never mix with your oil. You NEED to get the engine serviced immediately or you will be replacing it.
There are two fundamental ways water can get into the engine (other than sinking)...
1) An antifreeze leak from the engine cooling system.
Seadoo engines are cooled with a closed loop cooling system like a car. Antifreeze is circulated through the engine and the ride plate which acts as a radiator. I don't think this is the problem given the large volume of water shooting out, but you should check the color and level of the antifreeze on that engine. If it looks clean and at the normal level I would look at option 2 below. If it is not good, then you could have a bad head gasket or a leaking oil cooler.
2) A leak in the open loop cooling system.
This system cools two things using the lake or ocean water you ride in. Normally the jet pump forces water into the intercooler to cool the the air from the supercharger and from there it is sent to the exhaust manifold and muffler to cool the exhaust. When you run the engine out of the water you connect the garden hose to this system. This is where I think your leak is.
My first guess is a leaking exhaust manifold allowing water into the engine through the exhaust.
The other option is a leaking intercooler allowing water into the intake manifold. I don't think this is the issue given how the engine is running.
Regardless of the issue, you need to get the water leak issue fixed and perform the multi-step process to purge the water from your engine. Again this is something you need to do right away.