his price is way too low. All the "check out this ebook" sites I've seen, always charge $29 $37 $47. The reason for that is because most of these things get sold through affiliates, and with a high price you can offer someone $20-$30 per sale.
So web publishers will promote them more, since with an ebook, they have to sell someone a $37 product to get $30. While with Amazon, they'd need to convince them to buy a $1,000 product to get there.
There is plenty of competition from other internet marketing ebook sellers competing on adwords. This drives up the cost per click.
Unless you're targeting a few niche keywords then it is almost certain that the price will have to rise for adwords to be profitable (and as Vaksel mentioned to get affiliates).
I just checked out the ebook and improving google pagerank is a common topic so there's likely some tough competition in SEM.
My votes for a higher price or maybe find other marketing channels so you can keep it at $9.
So web publishers will promote them more, since with an ebook, they have to sell someone a $37 product to get $30. While with Amazon, they'd need to convince them to buy a $1,000 product to get there.