Age restriction to enter olimpics venues

Hello everyone
Im attending the olimpics next year, i have 2 sons (twins) aged 9 months, at the date of the olimpics they are going to have 2 years.
In the Hotels i have seen and asked for information, they enter without a cost
I can fly with them with not cost (In my arms) or pay 70% of an adult ticket to get a seat (I prefer this due to the time flying)
Also the Japan Rail pass is free unless i get a reserved seat, otherwise they can travel without a problem

But it seems there is no information anywhere that refers if the can enter for example at the inauguration event.
And if they need a ticket or can enter free if i seat them with me.

Anyone know something about it?

Thanks in advance for the help!

Therefs lots of information available; I found this on google in 10 seconds. I donft mean to be rude but, did you look?

https://tokyo2020.org/en/games/ticket/type/

All Games competition sessions including the Opening and Closing Ceremonies.

...

Ticket prices are the same for adults, children and infants (requiring a seat).
Admission will be free (no seat / no ticket required) for one child per one ticket holder, if the child is under the age of 2 (as of the competition day). If more than one child under the age of 2 will be entering the venue, tickets must be purchased for every child exceeding the above limit (one child per one ticket holder).This will also apply for venues without seats.

Could you believe me that i didnt read that part =/
Its not rude and i really apreciatte the help you provide me! you clear a doubt i had!
Thanks for your time!