5-digit unique/random/unpredictable alpanumberic id for eCommerce with min.10k id's,is this ok?

Can anyone specify the possibilities of -

1. Randomness?


2. Unique?


3. Safe and Secure to use?


4. User shouldn't identify the next generation number or previous one? from this

substr(str_shuffle(str_repeat("0123456789abcdefghijklmnopqrstuvwxyz", 5)), 0 , 5);

found this in - Generate random 5 characters string

Purpose of this is to display it as order-id for users in eCommerce site and i shouldn't get the duplicate,predict the next or insecure for the users.

Let's assume order per days will be 10,000. Which means i need at-least 10,000 unique order-id. Is this 5-digit unique enough to go-ahead?

In least-case i can use YYMMDD-XXXXX,but prefer without date,if possible!!