Welcome to the forums!
I'm sorry you are having problems with your budgies. By looking at how your budgies interact with each other and by paying attention to their body language and behaviours, you will be able to reach a conclusion and if need be to intervene and take the necessary steps to put a stop to the aggression.
The reason for the aggression can be hereditary, budgies who have violent parents can inherit the violent temperament. The aggression can also be potentiated when the budgie first comes into breeding condition.
If your Akira is now 7 months old, then most likely her cere is showing the mature dark brown colour
If Akira is constantly bullying Spikey, chasing him away from the food, swing or other toys, then in order to avoid an escalation on the fighting where Spikey can get severely injured, it would be best to house your budgies on separate cages.
By placing Akira on a separate cage you have better chances of making her go out of breeding condition (cere reverting to creamy white colour), this will also give her time to cool off. Later on, when they are both settled in their new housing arrangements, you can allow them to have closely supervised out of cage time together and depending on how they behave, you can keep up with it or not.
If the bullying continues, then having your budgies housed separately on a permanent basis would be the best choice and so will be giving them separate out of cage time.