Is it possible that I conduct a supervised machine learning like random forest after creating a target variable through clustering?
Generally speaking it is possible.
Somemore information would be helpful:
How do you plan to test/train? Do you want to use k-fold cross validation, or split the data? Are you going to use exactly the same variables as predictors in the Random Forest, that u used for the clusteranalysis? In this case you propably need to be careful with your interpretation since it is circular by nature.