So anyone can create a stakepool on main net and register it through the Cardano Foundation. No pools are ‘official’ they are all run by the community. Although IOHK do run pools too.
So what I think you are referring to here is the process in which we move over to the main net. IOHK will invite people currently running stakepools on the testnet to set their pools up in the Haskell testnet first. This is because they know these people can run successful and stable pools, which is required to run the network and be decentralised. However that doesn’t mean other people can’t set pools up, you just need to wait for that to be available.
As far as I’m aware, the plan is to run the Haskell testnet for a short time in two phases.
A time for pool operators set up their stakepools. Start by inviting a select few, then adding more before opening it up to every operator.
Then allowing ada holders to balance check their rewards. (As far as I know, you will not earn rewards on haskell testnet, the testnet is simply an exercise to allow pool operators to set a pool up using the haskell code and ada holders to check their rewards will be available to them).
Once this is complete a final date will be decided to move over to main net. I do not know if the process with pool operators will happen again, to prevent a mass influx of pools that are not run properly. Or if they will just allow all pools to go online straight away.
So to answer your question, yes if you want to run a pool you can. Your pool will not be anymore unofficial to other pools. It’s up to you to run your pool, maintain it and market it. Running a pool is a small business.