lol, seriously? A new account just to ask questions like these?

Joined: Today, 03:38 AM

1. My living place only got 4g but not 4g+, is it enough for 8 devices to use at the same time?
What kind of device are you using? Are you sure it has CA? Who or what are the 8 devices used for?
2. I have tested the speed by my postpaid plan and it can reach 30 to 70 Mbps, so will the infinite150 plan got the same speed?
More or less the same? Unless it's the device that's limiting the speed
3. If I shared the internet to 8 devices at the same time. Will the internet speed for everyone will be slower just like the fibre?
Slower than fibre? How "slow" is your fibre connection anyway?
4. After I reach 1tb quota of infinite 150, it will be capped to 10mbps so my 8 devices can have 10mbps speed or my 8 device will share the 10mbps?
Just request for a reset.

No fibre is that slow, lol.
What we want from fibre is the stability, so you will get a constant XXXMbps throughout the time.
As for wireless or mobile networks, it really is at "best efforts", if your area is congested or during peak hours, the speed varies.

Theoretically it should be split evenly, but there are just too many factors to reach that, unless you somewhat set up a QoS or speed limit on the intended router? 
It works the same, unless you get 8x i150 plans?

What should you be asking yourself is:
Are there any other fibre internet providers at your area?
Are there other mobile broadband packages that suit your needs better?
How is the i150 plan gonna benefit you? Speed? Mobility? All in one package?
How much is your budget for a decent CPE?