AusBonsai

I'm growing a Trident Maple bonsai for the first time. In the last 2 weeks it has started drooping. I want to transplant it as soon as possible. I'm planning to grow it indoor and I'm in Melbourne.

*** I currently have this at home:

- Pot Material: Stoneware, Dimensions/Size: 8.5cm (H) x 24.5cm (Dia.) Drainage hole: No

- Diatomite 2-7 mm 2 litres

*** I have ordered this and it's pending delivery approximately 2 weeks.

- Akadama potting medium 800g (hard, medium size 3-6mm)

I was going to also add some zeolite? This is also estimated roughly 2 weeks delivery and I'm not sure what size to get?

I would appreciate any recommendations.

That does not look quite like a trident maple. Where did it come from?
First up, trident maple is not usually considered suitable for indoors. Most trees really need sunshine and fresh air. Conditions inside our homes suit us but not most trees so many just deteriorate until they die which is likely what is happening to your tree now.
Soil mix is not really relevant. You can grow good bonsai in just about anything. It is just a matter of learning to mater to suit the plant and the mix it is growing in.
Growing a bonsai in a pot with no drain is really making life difficult for you and the tree. It is extremely difficult to gauge the real soil moisture under the surface so the roots may be dry or may be sitting in water down below and you won't know. Both are life threatening for the tree but most people don't recognize that until it is far too late.

Best indoor bonsai is ficus species. look for Port Jackson fig or the ubiquitous (but ugly) pot belly fig. Figs are tropical species that are adapted to low light levels and wet/dry seasons in the jungles so they can manage inside our homes.

Possibly Acer ginnala? (Amur Flame maple) Definitely leave it outside.

Thanks for the comments. My husband put a hole in the pot for me. I just purchased some premium bonsai potting mix from bonsaishop.com.au which I plan on mixing with diatomite. I also purchased some Bonsai Booster slow release Fertiliser 1 kilogram. I paid extra for quick delivery and estimated having this within the next few days. Would you recommend that I just put it outside now in the current pot even though it's cold and raining?

Yes put it outside even though it's cold and raining, it's the best environment for plants.

This looks like a very young plant. Far too young to make it into a bonsai. Best thing would be to plant it in the ground for a few years to thicken the trunk.