Community Milestones 9/9 unlocked

Actually you are wrong. According to this:

http://www.steamcardexchange.net/index.php?gamepage-appid-753

Maximum amount of EXP is 925 at this moment.

It gives you more time to join a good team the next day - the max. level you achieved isn't resetted - so you can join a lvl 300 game after reset if you where there before

Yup, but it'll only be a temporary glitch so don't get scared. You'll still be able to enter games at your real level. You'll lose all your money and abilities you've bought though (including your shields and everything)...