W9 or 1099 for paid caregiver wages?

You are most likely an employee in the eyes of the IRS, & boss owes "nanny tax" to cover your unemployment, worker's comp, etc. If you are a 1099 independent contractor it's got some criteria as far as the IRS is concerned (are you free to set your own hours, do you also have other clients, etc.). You might need to talk to someone about the whole situation, but it sounds like you are an employee. (the 98 hrs/week isn't necessarily OT -- if you are 24 hr caregiver some of the time can be considered "on call" rather than working (goofy, I know, when you can't leave), but that's how the government has "solved" the problem of 24 hr caregivers not getting paid OT. I would try to contact labor board or someone like that in your state to get details.

I think W2 is best. If you go on a 1099, you have to pay self-employment tax, which is the "employer's" portion of your social security and medicare taxes. Also, on a 1099, the employer is not required to do any withholding. You will regret that on tax day, unless you already know how to do estimated payments, due quarterly.

I worked at H&R Block, and don't recognize W9. So I think you mean W2.