If you are not going to use Multisite, then you would need to do the following:
1. Have myCRED installed and setup on your "main site".
2. On your second website, before enabling myCRED, add the following to your wp-config.php file:
define( 'MYCRED_LOG_TABLE', 'your_main_sites_mycred_log_table' );
Replace the dummy text with your main sites log table name so if your main sites db prefix is wp_ while your second site is other_ then the code would be:
define( 'MYCRED_LOG_TABLE', 'wp_myCRED_log' );
If you are unsure what the table name is, just go to your db admin area and check the table name. myCRED always names it myCRED_log but if you have been using myCRED since 1.0 then it might be mycred_Log.
3. Now enable myCRED on your second site and run the setup. Since the table will exist, myCRED will skip the install and you will be able to see your main sites log and users balance on your second site.
Now at this stage, both sites will share the log and since you are using the same usermeta table (where the balance is stored) on both sites everyones balance will be the same on both sites.
But this is where it ends. Since you are not using Multisite, you do not have access to the "Master Template" feature. This means that each site will have to be setup separate with regards of hooks and add-ons. If you want both sites to give the same amount of points then you will need to update myCRED on both sites to match.
The "Master Template" feature basically overrides all other sites settings with your main sites. But it requires Multisite and myCRED being network wide enabled.
I hope it all makes sense.
Let me know if you require further assistance.