I've seen on the iPhone version of Coin Dozer, it is possible to change the 4 stars into 5 stars (meaning you can use coins quicker).
Is this possible on Android? And if so how do I unlock it?
It is possible on Android. These screenshots were taken this morning from my S3.
When below 50 coins, only 4 stars are available:
But when you have 50 or more coins, 5 stars are available:
It may have been added in a recent update, but the Android version certainly can have 5 stars.
I think you can safely say the answer is no. There is no information on the internet to support an increase in stars at any level.
From personal experience, I have played the game to a near 100 level and have had thousands of coins and the number of coins available to drop at one time has not changed.
Thank you for your interest in this question.
Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.
Would you like to answer one of these unanswered questions instead?