I tried to keep it simple, but, I dont know how hard it is to do all of these things. I would appreciate any help as to how to do this, what materials I would need, etc. Thanks!
The project you've described is anything but simple. You've got some major requirements to meet there. Make no mistake about that.
Allow me address some of the requirements on your list (not necessarily in the order you listed them)-is small(no larger than a golfball)
This requirement alone is an extreme expectation. To build something as intelligent and capable as you've descried that is no larger than a golf ball, can fly, find bacteria, analyze it, kill it, and report the success rate, is a major design project. It would also require extremely specialized, miniaturized mechanics and electronics. If it is even possible, it would most likely cost a fortune to obtain the materials that small.
Something the size of a basket ball or American football would be far more realistic. Then you could use things like a raspberry pi for the intelligence, and still have room left over for all your additional sensors and disinfectant sprayers etc. -is aerial
You wouldn't want this thing to be a helicopter hovering over bacteria infested areas. The down draft from the props would only spread the nasty bacteria all over the place. So if you want it to be aerial the best bet would be to use something like a balloon, or zeppelin. Something that will float through the air using only sideways thrust. You would still need fans or some means to push air around to move but at least you wouldn't have the downward wash of a helicopter thrust blowing on the bacteria.-locate and identify common household bacteria and germs
Unless you have a way of having this thing actually sense potentially hazardous bacteria, your best bet it to just program it to periodically disinfect areas in the home that are known to be high bacteria areas.
Also, if you have this thing recognizing bacteria itself, be prepared that it might actually try to disinfect humans and pets. Since both humans and pets are usually covered with bacteria. -turn on and hover above bacteria population for x amount of time until the population is decreased by x percent
That part should be the easiest part of your entire project. What do you intend to use as your disinfectant? Some sort of aerosol spray? Don't forget that your robot will need to carry this equipment on board. How would you fit that into a golf ball sized robot?-record and report qualitive data about amount of bacteria found and killed into an app
How would you have the robot measure the amount of bacterial found or killed? Sometimes it's best to just tackle one problem like this one, and then you you have this problem solved, the resulting sensors and other equipment required for this task may already dictate how large your robot will need to be. -can be turned on, turned off, set to work at certain times during the day or for set amount of time, etc via an app
Well this could all be done in the app that controls the robot and would not need to be on board the actual robot itself. But you would still need to have some communications electronics on the robot. Again, fitting that all into a golf ball sized robot could be next to impossible. Especially if it needs to fly, sense bacteria, and disinfect bacteria too.-can work independently without human interference
This would depend partly on the controlling app, and partly one just how many sensors the actual robot itself has. Once again, there is a huge difference between what you can fit on a golf ball sized robot versus what you could fit on a football sized blimp. -recognizes and avoids humans and objects in its path
This alone is a major concern in any robot project. Especially when objects are random and unpredictable. -charges via solar power automatically
Just have it park in a place where the sun shines, and be sure it has (or can deploy) large enough solar panels.
This sounds like a very interesting project to be sure. Although the golf ball size restriction is most likely unrealistic. A football sized blimp would be far more realistic.
The first thing to do would be to get the blimp or zeppelin up and running. Try just getting the blimp to fly around the house where you want it to go without crashing into obstacles or humans. Once you get that far, you could then work on getting it to actually do things when it gets to certain locations within the home.
Good luck with this. Let's us know how you proceed with it.