for odaiba you can consider visiting this teamlab borderless. its a digital art museum. it can keep you occupied 3-4 hours.
https://borderless.teamlab.art/

i went to the other exhibition teamlab planets during sept which is also nearby odaiba.

there's a one day pass for odaiba Yurikamome line
Fares
Adult: 820 yen Child: 410 yen

please take note sept- oct is considered as typhoon season in japan. but its hard to predict when and where the typhoon will occur.
i was there this year 8-sept to 15-sept at tokyo.
weather was fine first 3 days is just sunny after that the weather pleasant not too warm. only one day of raining.
it was a gamble to go there during that period, keep on checking the weather forecast, looking at previous year weather data lol.

september-october have some autumn festival and other event going on.