9V rechargables are rare in use I don't think anyone makes a smart charger for them because they are not really a single cell but a pack of cells and vary in number of internal cells and capacity.
As for the C/D cells they are not mainstream for rechargables these days and the larger size would mean a heftier charger to get them charged faster which means more cost for those only wanting AA/AAAs recharged. when they start selling C/D nimh at more than 3000mah in the stores by major brand names then they will probably make bigger more powerful chargers but have to limit them mechanically somehow to prevent you from trying to charge a AAA nimh on a D cell setting of 4A or so....