WHMCS module is made the way that when i select coinpayments on the invoice, it do not wait untill i hit pay now button, but it automaticaly redirects to the gateway.

Other payment gateway modules i have waits for user to click pay now button. So here is how to modify coinpayments module to also wait for user to submit the pay now button:

Open /modules/gateways/coinpayments.php

And find the line:

$code .= '<script type="text/javascript">document.forms["cpsform"].submit();</script>';

comment out that line to become:

//$code .= '<script type="text/javascript">document.forms["cpsform"].submit();</script>';