There is no easy way to upgrade your Android operating system to 9.0 for free. However, there are a few ways to do it that are relatively inexpensive. One way is to buy a new phone that already has 9.0 installed, and then transfer your data over to the new phone. Another way is to download an unofficial version of 9.0 online and install it yourself. However, this can be risky, as there may be bugs or other issues with the unofficial version.