Can I setup my new Apple Watch Series 9 without an iPhone?

An iPhone is required to set up an iPhone. If you have an iPhone you can use Family Setup to set it up for them.

click here ➜ Set up Apple Watch for a family member - Apple Support

If you don't have access to an iPhone, then the Apple Watch cannot be used.

If you do use the Family Setup option, please note the limitations and restrictions listed on the link above.

SammyAb wrote:

Yes I have

Then you can set up their watches using your own iPhone under Family Set Up as explained in the link I provided above as long as they are the gps+cellular models.

please click here ➜ Set up Apple Watch for a family member - Apple Support

and carefully read the instructions there.

SammyAb wrote:

Oh ok thank you so I don’t have a choice I’ll buy again a phone both of them

No, you don't need to buy them iPhones. You can set up their watches using your own iPhone under Family Set Up as explained in the link I provided above as long as they are the gps+cellular models.

Correct. An iPhone is required to activate an Apple Watch in any scenario.

Without access to an iPhone in some form, you cannot set up an Apple Watch.

Setting up an Apple Watch requires a compatible iPhone. Please review the Apple Support article I have shared below. It explains setting up and Apple Watch.

Get started with Apple Watch - Apple Support

You sort of can, if you have a compatible iPhone. Do you have an iPhone? Do you have one Apple Watch or two, one for each parent?

Please review Phil0124 post and link in his above post. It details how to setup up Watches using your compatible iPhone.

Do you have an iPhone?