It is not really possible to answer this in a quantitative way that is clearly correct. It is not possible to measure innovation and degrees of innovativeness and to correlate those things with inexperience or knowledge. Instead, we should note that both kinds of people can be innovative, but that some people think that inexperience helps bring about innovation.
People who are knowledgeable certainly can be innovative. They know a particular area inside and out and may have a good sense for what sorts of changes are needed. This allows them to innovate.
However, it is possible to argue, as the famous entrepreneur Richard Branson does in this article, that inexperience is very beneficial. People who are inexperienced do not know the conventional wisdom in a given area. They are not aware of all the things that supposedly cannot be done. Therefore, they are more likely to try things that more knowledgeable people would not try. Because of this, their inexperience and lack of knowledge can be a real plus for them.
Thus, while we cannot quantify the extent to which each sort of person is innovative, it is certainly possible that inexperienced people will be more innovative than knowledgeable people