If I am not wrong once IPL hosted with 9 teams which includes Kerala but they never appeared anymore.
Team Kochi was banned because the team failed to provide the bank guarantee and there was a legal battle and the team owners won the case and BCCI was asked to pay over 500 crore INR but no idea whether it is settled or not. If more teams are added there is a possibility that Kochi will get a team if the BCCI did not pay that settlement.
Kerala played IPL in 2011 and ten teams has participated on that season. As far as I know BCCI hasn't payed the amount back to Kochi Tuskers Kerala yet. For this BCCI may accept Kerala as new team in next IPL season. Although it will depend on the franchise. Maybe they will compromise the due amount by getting their chance in IPL.