The exponential growth model is given to be:

where a is the initial amount and r is the growth rate in decimals.
The growth rate is given to be 9% per year. This means that:

In the year 2012, there were 22,900 foxes. This means that:

Therefore, the model will be:

where f(x) is the fox population after x years after 2012.
The year 2020 is 8 years after 2012.
Therefore, the fox population will be:

The estimated fox population is 45,630.