Yes, you can open and convert the old v8 projects. Please refer to this link for further info www.websitex5.com/v8tov9

After converting project from v8 to v9 and uploading it, will I be able to use v8 to upload my project from within v8 if I will not be happy with the look of my website after converting it to v9? Is there any way of keeping older version of the project or is it going to be completely lost after conversion? 

The WebSite X5 Evolution 8 IWP file will not be changed, so, if you want, you'll be able to reexport your project with this version.

is this conversion also available with the v9 Compact version?

I've just bought the v9 Compact version (besides the v8 Evo) to see the changes. We have still the v8 installed in the classroom but the students will buy the latest version and I need to know the differencies.

But as I can see there are many features trimmed down that I wouldn't have expected .

And it looks like the import of .iwc files as well

Dear Ueli,

you can not import your projects from Evo 8 into Compact 9, you can import them only from Evo 8 to Evo 9 and from Compact 9 to Evo 9.

There are 200 new features in Evo 9, please have a look at this page http://www.websitex5.com/en/what-s-new.html where you will find all the info you need regarding them. We haven't removed many functions, maybe you can not find them? What exactly are you looking for?