So it's gonna be
One month for Venture Bros
Two months for Steven Universe
Three months for JoJo's
This wait becomes less painful each time

Misinformation! New episodes are not coming in September https://www.regularcapital.com/2018/07/cartoon-network-australia-and-boomerang-australia-september-2018-highlights/ and https://www.regularcapital.com/wp-content/uploads/2018/07/CartoonNetworkSeptember2018Highlights.pdf) is where this orginates from.

Notice where it says AUSTRALIA. Also read the description "Steven Universe is always trying to save the day with the help of the Crystal Gems but what happens when the Crystal Gems are the ones that need the help? After some shocking revelations about their former leader, Rose Quartz, the group is divided and it is up to Steven to bring the group back together." It is clearly describing the events of Heart of the Crystal Gems. In other words September is when Australia will be premiering the episodes from The Heart of the Crystal Gems, not when will get new episodes.

But

Joe Johnston (one of the writers of the show) said that they plan to make an announcement at SDCC 2018 in two weeks.

http://joethejohnston.tumblr.com/post/175625899178/glad-everyone-enjoyed-this-weeks-episodes