Yup, they can be trained. My parents neighbours took in a feral cat, about 1.5-2 years old. She HATED baths at first, literally had to get the oven mitts and eye protection for a quick wash.

Then in 6 months they managed to desensitise her to water, and she now BEGS to be bathed every week.

My childhood cat had ringworm and had to be bathed with special shampoo for a while. He always loved human attention, so he loved the part where my mom wrapped him in a towel and packed him around. He loved it so much he'd come running when the water turned on, even though he didn't really love the bath itself.

Also having a non-slip surface can help a lot, since quite a few cats freak out when they slip on surfaces, AFAIK.

Our cat used to take showers with my spouse before I moved in. She doesn't anyone, but she does still barge in to make sure the spouse is being safe.