SoftBank will still use its Naoqi operating system to control Pepper's hardware -- Android will only run on its chest-strapped tablet. The company isn't saying what sort of business deal it's struck, but Google typically takes a 30 percent cut from Android app revenues. We also don't know how much the robot will be able to take advantage of Android's features. The recently announced Google Assistant AI could actually be useful in a humanoid robot that can move on its own.
SoftBank is still trying to figure out a purpose for Pepper, hence the need for more developer interest. As an experiment, it staffed an entire phone store with several Pepper units earlier this year, but that was only temporary.