Can we do the awards for both endurance and speed after each age group?

No.  Per FINA guidelines, podium for all finishers will be presented upon the conclusion of each division for both Speed and Endurance.

As an example, upon the completion of the 6-8 age group Speed Event, a podium will be presented for all Finishers of the Speed Event in the 6-8 age group prior to moving on to the next group on the schedule.