I want to annodize my hubs but they have steel cups. Anyone know a good way to mask the cups so they dont disolve in the sulphurinc acid?

Knock 'em out with a drift punch and press them back in after you get the hubs back from anodizing.

Are these bottles of spray paint as good as getting something anodized?

https://www.krylon.com/products/xmetals/

https://www.duplicolor.com/products/metalcast.html

Can you do that with Shimano hubs?

I was thinking of recommending filling the hub with melted wax to mask the races and them melting it out with boiling water after the hubs are anodized.

Nope, there's a translucent 3D clear finish to anodizing (the hexagon cells are aimed vertically on the surface). I haven't found any paints to give a nice finish similar to anodizing. Although Alsa does have some chrome-like paint that's very, very close to the real thing.

I don't know about the process he'll be using, but commercial platers use hot baths for the cleaning and etching. I'd be afraid the wax would melt. Otherwise it's a good idea - wax is impervious to just about anything chemical.