Is there a way to Group Grid with + - buttons (like the pivottable)? Has anyone accomplished this or something similar?

I use the expanders sometimes. I suppose it's based on what you are trying to accomplish with the expanding of the data. They work great.
What are you trying to do?

Similar to the capabilities to the grouping features, with added summaries. I like the grouping however I can't get it working on Ipads or mobile devices. Is there a solution to that?

I don't have any mobile issues. Usually that has to do the the doctype html header in regards to the page behavior on a mobile device. Also Apple has their own webkit you have to include in the css for page scrolling and fonts.
Also, the "+" and "-" sign are a bit small. You may need to use a custom column to display a larger icon to tap.
You'll have to use the koolgrid's javascript object to call the expand methods.
You can basically expand as much as you need.
Have you started your project yet, or mapped it out on paper? If not, check out their expander demo. It's pretty straight forward.
http://demo.koolphp.net/Examples/KoolGrid/Hierarchy/Three_Levels_Hierarchy/index.php