If you search for "wm8505 linux" you should find the kernel community and some ready distros. But given it's a consumer device built for android, it may requre some effort to get it running something else.
The netbooks usually are easier than the tablets, but YMMV.
On the CPU freq, if it's not possible to adjust directly, you can use cpulimit to make sure your app only uses X% of the cpu. Should be almost equivalent.