Changing the metamask display decimal of non erc-20 token

In order to support evm like transactions, we have implemented the RPC interface of Ethereum. But our gas token’s decimal is 9, which leads to the display error of metamask (ETH’s decimal is 18). Anyone can help me solve the problem? txs

This question may be better asked in the developer questions.
The decimal value on Metamask can be edit by users.